Okavango River Basin Trans-Boundary
Diagnostic Assessment (TDA):
Botswana Component
Partial Report
Key Public Health Issues
M.J. Chimbari
L. Magole
Harry Oppenheimer Okavango Research Centre
June 2009
TDA Botswana Public Health
OKAVANGO RIVER BASIN TRANS-BOUNDARY DIAGNOSTIC
ASSESSMENT (TDA): BOTSWANA COMPONENT
Partial Report
KEY PUBLIC HEALTH ISSUES IN THE OKAVANGO
BASIN, BOTSWANA
Coordinated by Dr L. Magole
Harry Oppenheimer Okavango Research Centre (HOORC), University of Botswana
Report prepared by Professor M.J. Chimbari
Contract:
June 2009
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TDA Botswana Public Health
EXECUTIVE SUMMARY
This report addresses key health issues in the Okavango Delta and its riparian areas as part of
the Botswana component of the Okavango River Basin Trans-boundary Diagnostic Assessment
(TDA). The analysis identified potential health risks and hazards, initially screened them and
analysed those considered to be important on the basis of the initial screening. The analysis
used a combination of TDA and Health Impact Assessment (HIA) methodologies.
In the initial screening schistosomiasis, malaria, trypanosomiasis, filariasis, cholera, diarrheal
diseases, chemical poisoning, malnutrition and injuries were identified as potential health
hazards. Of these potential hazards only schistosomiasis and malaria were subjected to
detailed analysis as their risk in the context of TDA and their associations with water were
classified as very high.
Previous publications indicated that transmission was once very high in Ngami district
particularly in Maun but was controlled to a point where its public health importance became
insignificant in 1993. Since then no other studies were conducted and notification of the disease
became so relaxed resulting in possible underreporting of cases. However, snail surveys
conducted as late as 2009 show that the intermediate host snails for both Schistosomiasis
haematobium and Schistosomiasis mansoni are present within the Delta and the Boro and
Thamalakane rivers. This suggests that transmission could be going on unnoticed. The study
also noted that transmission of schistosomiasis was dependent on the flood regimes as snail
abundance snails and intensity of water contact activities in the Boro and Thamalakane rivers
depended on that. Furthermore the study predicted that the problem of schistosomiasis would
increase due to the current (2009) floods and that expansion of irrigation activities planned for
Shakawe would increase transmission of schistosomiasis. The current capacity to diagnose
schistosomiasis within the district is considered to be weak and health posts in areas within the
Delta face serious challenges in health service delivery.
Previous studies and analysis of data obtained from the Ngami District Council showed that
malaria is a major problem for at least 6 months in a year with sporadic cases throughout the
year. Transmission of malaria was shown to follow the rainfall pattern with a lag period of 3
months and some association with water discharge at Mahembo was established. Temperature
was not considered to be a major limiting factor as average temperatures do not drop below the
critical temperature (for malaria parasite development in the mosquito) of 180C for prolonged
periods. Although the high clinical cases of malaria in comparison to confirmed cases indicated
poor clinical diagnosis there was a close association between the confirmed and unconfirmed
cases of malaria. There is a functional malaria control programme in the district but there are
problems of health facilities accessibility during the rainy season and during times of high floods.
Furthermore the need to strengthen capacity of the health posts was identified. The plans to
expand irrigation activities in the Shakawe area are expected to exacerbate the malaria problem
in that area if preventive and mitigation measures are not incorporated into the irrigation
designs.
The study concluded that although there are several potential health hazards associated with
water inflows into the Okavango Delta and rainfall, the hazards that need to be monitored
closely are malaria and schistosomiasis. Monitoring of malaria was considered to be easier if
done in the context of the ongoing control programmes but monitoring of schistosomiasis was
considered to be difficult since there is no operation control programme. Emphasis to monitor
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malnutrition, cholera and diarrheal diseases during periods of unusually high rainfall and high
floods was made.
In view the uncertainty regarding climate change with regards rainfall it is recommended that
studies that determine the possible impacts of the wet and
dry scenarios of the Okavango Basin on diseases, particularly malaria and
schistosomiasis be carried out.
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TABLE OF CONTENTS
EXECUTIVE SUMMARY .............................................................................................................. 3
TABLE OF FIGURES ................................................................................................................... 5
TABLE OF TABLES ..................................................................................................................... 6
1. BACKGROUND AND SCOPE .............................................................................................. 7
2. METHODOLOGY .................................................................................................................. 7
3. RESULTS .............................................................................................................................. 8
3.1
Identification and initial prioritization of health problems ........................................ 8
3.1.1 Communicable diseases ................................................................................................ 8
3.1.2 Non-communicable diseases ........................................................................................ 9
3.3 Final prioritization of the public health problems ............................................................... 12
3.3.1 Schistosomiasis .......................................................................................................... 12
3.3.2 Malaria ........................................................................................................................ 14
4. CHAIN AND GOVERNANCE ANALYSIS ........................................................................... 19
5. CONCLUSIONS .................................................................................................................. 21
6. RECOMMENDATIONS ....................................................................................................... 22
7. REFERENCES .................................................................................................................... 23
TABLE OF FIGURES
FIGURE 1. PREVALENCE OF SCHISTOSOMA MANSONI INFECTION RECORDED
AMONGST PRIMARY SCHOOL CHILDREN IN THE VICINITY ........................................ 12
FIGURE 2. ANNUAL FLOW OF THE THAMALAKANE RIVER (LINE) AND PREVALENCE OF
S. MANSONI (BARS) IN THE MAUN AREA FROM 1952 TO 1999 ................................... 13
FIGURE 3. MALARIA TRANSMISSION ZONES IN BOTSWANA ............................................ 14
FIGURE 4. INFLUENCE OF RAINFALL ON MALARIA INCIDENCE
(WWW.ROLLBACKMALARIA.ORG/COUNTRYACTION/BOTSWANA.HTML) .................. 15
FIGURE 5. UNCONFIRMED AND CONFIRMED MALARIA CASES IN NGAMILAND .............. 15
FIGURE 6. NUMBER OF UNCONFIRMED (A) AND CONFIRMED (B) CASES OF MALARIA
AMONG CHILDREN BELOW 5 YEARS AND THOSE 5 YEARS AND OLDER ................. 16
FIGURE 7. CASES OF UNCONFIRMED MALARIA PLOTTED TOGETHER WITH MONTHLY
RAINFALL RECORDED AT SHAKAWE (A) AND WATER DISCHARGE AT MAHEMBO . 17
FIGURE 8. MINIMUM, MAXIMUM AND AVERAGE (OF MINIMUM AND MAXIMUM)
TEMPERATURES RECORDED AT SHAKAWE ................................................................ 18
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TABLE OF TABLES
TABLE 1. INITIAL PRIORITIZATION OF PUBLIC HEALT PROBLEMS IDENTIFIED IN THE
OKAVANGO DELTA ........................................................................................................... 10
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1. BACKGROUND AND SCOPE
This chapter contributes to the Botswana component of the Okavango Basin Trans-boundary
Diagnostic Assessment (TDA). The chapter focuses on public health aspects that are directly
influenced by water resources and limited to the Okavango Delta and its immediate
surroundings. HIV/AIDS issues, though critical in determining use and management of water
resources management, are not dealt with in this chapter as there is a chapter focusing on that.
Thus, this chapter mainly deals with diseases transmitted by intermediate hosts based in water
(water based diseases), diseases transmitted by insect vectors that breed in or near water
(water related diseases), diseases contracted by drinking contaminated water (water-borne
diseases) and diseases caused by lack of hygiene (water washed diseases).
2. METHODOLOGY
The general methodology for TDA constituting five steps was adopted for this chapter. The
steps followed are i) identification and initial prioritization of public health problems, ii) analysis
of impacts and consequences of the identified problems, iii) final prioritization of the public
health problems and iv) causal chain analysis and governance analysis. The production of a full
TDA (v; step 5) is not covered in this chapter as that will be done for the overall component. The
analyses for the various steps was done in accordance with the 3 standard components of
Health Impact Assessment (HIA); community vulnerability (extent to which a community is exposed
to a risk), environmental receptivity (extent to which environmental factors provide conducive
conditions for disease transmission) and capacity of health services and other protection agencies
(extent to which health services or protection agencies are able to deal with a given risk or hazard)
(Birley, 1991). In doing that, studies that have been conducted in the Okavango Delta were
reviewed and trend analysis of health statistics from the health facilities in the Delta was done.
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3. RESULTS
3.1 Identification and initial prioritization of health problems
Using regional diseases distribution maps, Botswana national health information system and
published material, potential water related public health problems for the Okavango Delta were
classified into 4 groups; communicable diseases, non-communicable diseases, malnutrition and
injury.
3.1.1 Communicable diseases
Schistosomiasis was considered a major problem in Ngamiland in the 1980s with prevalences of
up to 80% for Maun. A recent study (Appleton et al. 2008) predicted that another epidemic is likely
to occur in Maun in 2020. Both intermediate host snails for Schistosoma haematobium and
Schistosoma mansoni are present within the Delta and in channels flowing out of the Delta. Thus,
schistosomiasis was considered to be a problem needing further investigation.
Malaria is endemic in Botswana and is ranked as one of the major public health problems that
must be reported routinely by the Ministry of Health. The available records for the years 1998 to
2003 showed that amongst the five notifiablle diseases (diarrhea, confirmed malaria, viral
hepatitis, measles and rabies exposure) in Botswana, malaria was second to diarrhoea in terms
of cases and deaths recorded in all the years. Analysis of 2007 health statistics for Maun
showed that cases of malaria were reported throughout the year. The malaria vector is present
within the Delta and generally in Ngamiland. In view of this malaria was considered to be a
problem needing further investigation.
In Botswana African trypanosomiasis was only a problem in the Okavango Delta. Many years
of control efforts backed by a strong political will and financial support have yielded very good
results. This zoonotic disease is currently not of public health importance but there is need for
continued surveillance.
Filariasis has not been reported in Botswana, South Africa, Namibia, Swaziland and Lesotho. It
is therefore not considered to be a potential important problem in the Delta.
Cholera cases were in 2008 detected in Francis town which is close to the Zimbabwean border
but it did not spread in the country. The Delta is prone to flooding and cholera is a potential
problem if pit latrines are flooded and drinking water is contaminated. For this reason cholera
has been considered as a problem that may need to be monitored.
Diarrheal diseases
Outbreaks of diarrheal diseases are often associated with unusually high rainfall and poor water
and sanitation facilities. In 2006 Botswana (mostly east and south eastern areas) experienced
an outbreak of diarrhea caused by Cryptosporidium spp. The parasite is found in water, soil and
food and is transmitted through ingestion. Cryptosporidium infections result in high case
fatalities due to poor diagnostic capacity and complications due to malnutrition and HIV.
Although there is a potential risk of contamination of drinking water from waste disposal systems
in the Delta, McCarthy et al. 2004 demonstrated that transpiration by island vegetation salinized
ground water and reduced movement of pollutants while the sandy soils were found to exhibit
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significant filtration effects on bacteria. In view of the 2009 floods in the upper Delta resulting in
flooding of water purification and some sanitary facilities it is important to monitor the situation of
diarrhea in these areas.
3.1.2 Non-communicable diseases
Chemical poisoning is the only non-communicable condition that is considered to be
potentially important particularly if irrigation activities expand resulting in increased use of agro-
chemicals. Water quality monitoring done in the delta has not shown significant amounts of
harmful contaminants.
3.1.3 Malnutrition
The Okavango Delta currently supports riparian communities with a reliable source of protein.
Any changes that may affect fish abundance may also affect the nutritional status of
communities that rely on fish as a source of protein. Furthermore any outbreaks of diarrhea due
to Cryptosporidium spp that may result from flooding may increase fatalities among
malnourished and HIV positive children. On another positive note expansion of irrigation
development may improve the nutritional status of riparian communities by increasing their
incomes and introducing more protein sources for their diets. The 2006/07 Ngami Annual
Report reported an increase of severe malnutrition among children from 0.2% in 2006 to 0.3% in
2007 and also an increase of total malnutrition from 1.3% in 2006 to 1.4% in 2007.
3.1.4 Injury
Injury is likely to occur during periods of floods and occasionally from attacks by animals like
crocodiles and hippos.
3.2 Analysis of impacts and consequences of the identified problems
Importance of each public health problem identified during step 1 was ranked by assessing
community vulnerability, environmental receptivity and capacity of health services and other
protection agencies. Table 1 shows the analysis resulting in the prioritization.
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Table 1. Initial prioritization of public healt problems identified in the Okavango Delta
Disease
Community vulnerability
Environmental factors
Health service capability
Prioritization of
diseases
Schistosomiasis
· Fishers
have · Intermediate host snails · Access to health posts Very high risk
occupational vulnerability
have been observed at
sometimes difficult
· Children and women
sites in the delta
· Drugs may run out
living close to water · Cases of schistosomiasis · No diagnostic facilities
courses are vulnerable
are reported at health
posts
Malaria
· Lodge workers and other ·
Mosquito vector for
· Access to health posts Very high risk
communities living close
malaria is present within
sometimes difficult
to water are vulnerable
the delta
· Drugs may run out
· Malaria cases reported at · No diagnostic facilities
health posts
Cholera
· Communities relying on · processing of fish may No outbreaks have been Low risk as no outbreaks
fish may be vulnerable
lead to contamination
reported
have been reported
Diarrheal Diseases
· Communities within the · Diarrheal disease cases Access to health posts Medium risk
Delta and on the reported at health posts
sometimes difficult
outskirts of the delta that
have no safe water are
vulnerable
Filariasis
· The
geographical · The potential vector for · Health system has no Low risk as disease is
distribution of the the disease is present
capacity to deal with rare or absent in
disease does not extend
the problem at local Botswana
to Botswana
level
African
· Communities living in or · The vector (tsetse fly) · Protection agencies Although cases have only
trypanosomiasis
near the Delta are
responsible for
responsible for control been reported in th past
exposed to the disease
transmission of the of the disease have the level of risk is medium
disease is present
done very well in and the situation needs to
controlling the vectors
be monitored.
· Control programme
has been well funded
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and given sustained
political support.
Chemical poisoning
· Communities drinking ·
Water quality is
· Currently capacity to Low risk as water quality
raw water may be
dependent on
deal with cases of analysis has not shown
vulnerable to chemical
developments that may
poisoning is weak
presents of significant
poisoning (arsenic, lead,
take place in Namibia and
contaminants.
flouride, etc.)
on the agricultural
expansion programme
proposed by Botswana
government
· Ongoing monitoring has
not shown significant
quantities of contaminants
Malnutrition
· Fish abundance in the · Reduction in fish stocks · Plans to expand Low risk as fish stocks are
Delta is good for the
due to pollution or over-
irrigation activities will not likely to seriously
nutrition of the riparian
fishing can seriously provide source of
decline because of
communities
affect the community's
income and alternative measures put in place
nutritional status
sources of protein
and plans to diversify
· Legislation to regulate livelihoods of riparian
fishing in order to communities will provide
sustain the resource is other sources of protein
in place
Injury
· Communities are largely · Delta waters are infested · There is limited Accidents do not happen
involved in water related
with crocodiles and capacity to deal with often but when they
occupations that place
hippos and there are
serious injuries
happen there is little
them at risk of being
many dangerous
capacity to deal with the
attacked by wild animals
terrestrial animals that live
situation thus making the
and drowning
within the delta
risk medium.
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TDA Botswana Land Use Planning.
3.3 Final prioritization of the public health problems
Based on the screening and scoping done in steps 1 and 2, respectively a decision
was made to further assess the problems of schistosomiasis, malaria and diarrheal
diseases.
3.3.1 Schistosomiasis
Schistosomiasis has been reported as an important public health problem in the
Ngamiland /Chobe regions of Botswana. In a survey conducted between October
1976 and October 1978 the prevalence of S. mansoni in Ngamiland/Chobe regions
was reported to be 24 % (Rudo, 1979). Areas where S. mansoni was present
included Sepopa, Seronga, Gomare, Nokaneng, Tsau, Maun and Shorobe while no
schistosomiasis was detected in Sehitwa and Toteng. Several authors have indicated
that in Maun there has been a gradual increase in prevalence of schistosomiasis that
reached a peak of 80.5% in 1986 (Friis and Byskov, 1987), a period that coincided
with the period just after high inflows of floods in the Thamalakane river and the rapid
population increase in Maun village. A control programme based on treatment of
infected people was successfully carried out from 1985 to 1993. S. mansoni
prevalence dropped from 28.7% 1985 to 6.7% in 1993. Consequently, the cases
reported at the hospital were reduced to about 1 case/month with the result that
notification of the disease was relaxed. The current situation of schistosomiasis in
Maun is not known as there have been no other active surveys and the notification
of the disease has remained relaxed. Figure 1 shows trends of schistosomiasis
prevalence in Maun as reported by Appleton et. al. (2008).
Figure 1. Prevalence of Schistosoma mansoni infection recorded amongst
primary school children in the vicinity
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As part of the Rapid Biological Assessment of the Aquatic Ecosystems of the
Okavango Delta (AquaRAP 2000), a survey of freshwater invertebrates of the
Okavango Delta was conducted. The survey was conducted in four focal areas within
the Okavango Delta: Upper Panhandle (UPH), Lower Panhandle and Guma Lagoon
(LPH), Moremi Game Reserve (MGH), and Chief's Island (CHI). Both Bulinus
globosus and Biomphalaria pfeifferi snails, intermediate hosts for transmission of
Schistosoma haematobium (urinary schistosomiasis) and Schistosoma mansoni
(intestinal schistosomiasis) respectively, were found in all the focal areas with
B.pfeifferi being more widespread. Although the survey was not extended to the
Thamalakane river that passes through Maun Village, the report concluded on the
basis of literature available that transmission of schistosomiasis was dependent on
the floods regimes of the Delta suggesting that transmission in Maun increased
during years when annual inflow of floodwater into the Thamalakane River was high.
This is illustrated in Figure 1 published by Appleton et al. (2008).
Figure 2. Annual flow of the Thamalakane River (line) and prevalence of S. mansoni
(bars) in the Maun area from 1952 to 1999
Given that in 2007 and 2008 Thamalakane river maintained a steady flow, there is a
possibility that schistosomiasis prevalence levels may rise to levels comparable to
those experienced between 1976 and 1980. Appleton et. al. (2008) projected that a
schistosomiasis epidemic similar to the one of the 1980s will recur in 2020. Chimbari
(personal communication) is currently assessing the situation of schistosomiasis in
Maun through parasitology and snail surveys. The study, which has already identified
intermediate host snails at sites along the Boro river which feeds into the
Thamalakane river, will also determine the association between schistosomiasis
prevalence, snail abundance and the delta flooding regimes. At present there is no
schistosomiasis control programme being implemented in Ngamiland. If plans to
expand irrigation activities in the Shakawe area proceed the implications on
transmission of schistosomiasis will be increased snail habitats and direct human
water contact which will increase the transmission rate. Possible increased floods
during the Delta flooding increased flooding cycle may increase Molapo farming
(flood-recession farming) practice as floods extend to areas that have not been
flooded for many years. This will increase human water contact thereby increasing
the risk of people to contracting schistosomiasis.
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3.3.2 Malaria
3.3.2.1 Country overview
Almost 2/3 of Botswana is malaria free. The remaining 1/3 which is mainly the
northern part of the country experiences a 4-6 months period of malaria
transmission. According to WHO (2002) the number of deaths due to malaria
recorded nationwide were 141, 23, 49, 30, 29 and 14 in 1997, 1998, 1999, 2000,
2001 and 2002, respectively. As indicated in Figure 2 the Okavango Delta lies in a
belt where transmission takes place for 4-6 months (MARA/ARMA, 2001). In much
of the malaria endemic area transmission follows the rainy season with a lag of about
2-3 months as indicated in Figure 3.
Figure 3. Malaria transmission zones in Botswana
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Figure 4. Influence of rainfall on malaria incidence
(www.rollbackmalaria.org/countryaction/Botswana.html)
3.3.2.2 Situation in Ngamiland
Analysis of cases recorded in 2004 and from 2006 to 2009 in health posts in
Ngamiland, where the Delta is situated, shows that both clinical and confirmed cases
of malaria were recorded throughout the year (Figure 4). Consistent with the MARA
predictions, most of the clinical cases were between December and April. As
expected, confirmed cases were fewer but also spread throughout the year with most
of the cases in the December to April period. The highest number of recorded
deaths were in 2009 (12 cases) followed by 2006 (5 cases). There were 2 deaths
recorded in 2008 and none in 2007. For both confirmed and unconfirmed cases
children under the age of 5 years had fewer cases than those 5 years and older
(Figures 5a and 5b). However, the total number of deaths for children under 5 years
old were higher (18 deaths) than for those 5 years and above (1 death).
Figure 5. Unconfirmed and confirmed malaria cases in Ngamiland
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a)
b)
Figure 6. Number of unconfirmed (a) and confirmed (b) cases of malaria
among children below 5 years and those 5 years and older
.
The monthly distribution of cases in the period January 2006 to April 2009 seems to
have been determined by both rainfall and discharge of water at Mahembo (Figure
6a and 6b). The rainy season usually starts in November and ends in March, a
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period during which most of the malaria cases were recorded. Thomson et al. 2005
demonstrated the use of rainfall monitoring for malaria early warning in Botswana. In
the period 2006 to 2009 the peak discharge of water at Mahembo was in May for
2006 and in April for the rest of the years. In 2007 and 2008 cases of malaria were
recorded in October, November and December while very few or no cases were
recorded in the same period for 2006, a year that was characterized with much less
water discharge at Mahembo. Data for 2009 is only up to April. It should be noted
that the discharge of water largely has influence in lower areas of the delta and
further downstream where some areas are without water in some months of the year
than in the panhandle and middle of the Delta where there is water throughout the
year.
a)
b)
Figure 7. Cases of unconfirmed malaria plotted together with monthly rainfall
recorded at Shakawe (a) and water discharge at Mahembo
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Temperature is a key determinant of malaria transmission. If temperature falls below
18oC for extended periods parasite development in the mosquito stops and therefore
transmission is significantly reduced. Figure 7 shows the minimum, maximum and
average (of minimum and maximum) temperatures recorded from January 2006 to
April 2009. The minimum temperatures were far below 18oC from May to August, a
period during which very few clinical cases of malaria were recorded. It should
however be noted that the average temperature was close to 20oC suggesting that
transmission may not have been completely stopped because of low temperatures.
Figure 8. Minimum, maximum and average (of minimum and maximum)
temperatures recorded at Shakawe
The Ngamiland local authority and Ministry of Health prioritize malaria and therefore
have an operational control programme consistent with the national control
programme. In 2007/2008 the annual coverage of house spraying using
deltamethrine was 80%. The chemical currently used is DDT. The control
programme also includes supply of Insecticide treated nets (ITN) at a cost of P20 per
net and awareness campaigns. According to the Ngami Annual Report of 2006/07
the district maintains an all year round malaria vigilance. As argued for
schistosomiasis if plans to expand irrigation activities go ahead more breeding sites
for the anopheline mosquito will be created thereby increasing the force of malaria
transmission. Furthermore, possible increased Molapo farming (flood-recession
farming) due to extended flooded areas may result in increased malaria transmission
as more mosquito breeding sites will be created as the floods recede. The potential
areas where Molapo farming may occur have been mapped.
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4. CHAIN AND GOVERNANCE ANALYSIS
The situation analysis of health aspects in the Okavango Delta identified 9
potential health risks. At the initial prioritization stage cholera and diarrheal
diseases were classified as currently low risk hazards but need to be monitored
particularly when unusually high discharges of water at Mahembo or an unusually
good rainy season is expected. Despite the great successes registered in
containing the African trypanosomiasis in Botswana, the need to monitor this
zoonotic disease classified as a low risk hazard was highlighted. Chemical
poisoning and malnutrition were rated low in view of the encouraging results
being obtained through the water quality monitoring and the nutritional monitoring
programmes. Injuries were classified as medium risk needing constant
monitoring. The risk was considered to be mainly associated with interactions
between animals and people. In view of the fact that filariasis has not been
detected in southern African countries it was considered to be a very low risk that
should not be monitored.
Schistosomiasis and malaria were rated highly as potential hazards determined
by both rainfall and water inflows from the upper Okavango River. For
schistosomiasis to be transmitted the appropriate intermediate host snail must be
present, there must be human water contact activities and the parasite must be
present in the locality. All these conditions are met. Studies conducted in the past
clearly indicate the association between water inflows into the delta and
abundance of intermediate host as well as prevalence of the disease. S. mansoni
seems to be the dominant schistosome species mainly because Biomphalaria
pfeifferi, the intermediate host of that schistosome is more widespread in the
delta. There is a wide range of groups of people that are vulnerable to
schistosomiasis including children who swim in the river, particularly downstream
of the Delta, fishers, tourists, women harvesting reeds and the workers in tour
operator lodges. The capacity of health institutions and other protection agencies
with regards to schistosomiasis diagnosis and control is weak. There is no control
programme in place and very few or no cases of schistosomiasis are being
recorded at health posts indicating poor diagnostic capacity or low prioritization of
the disease. The study that has just been initiated in Maun may show the current
situation of the disease leading to reprioritization of the disease. The heavy floods
experienced in 2009 may result in several years of maintained flows in the
Thamalakane and lower river systems thereby increasing the risk schistosomiasis
to riparian communities.The proposed expansion of irrigation activities in
Shakawe will need to be accompanied by a Health Impact Assessment (HIA) in
order to incorporate disease preventive and mitigation measures in the designs
and operations of the irrigation scheme.
The anopheles mosquito responsible for malaria transmission is present in the
Okavango Delta and surrounding areas. This mosquito breeds in clear shallow
water. The hoof prints left by animals on the edges of water channels are perfect
breeding sites for the anopheles mosquito. This therefore creates good breeding
sites for mosquitoes outside the rain season. During the rainy season the number
of breeding sites is increased and as shown by the analysis of health centre data
for Ngamiland and national data the trend of malaria transmission is largely
influenced by rainfall. Temperature was shown to be not a limiting factor in the
transmission of malaria in the Delta and surrounding areas as the average
temperatures do not fall below 180C for extended periods there by having little
effect on malaria parasite development. Communities in tour operators' lodges
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and tourists are vulnerable to malaria. However, tourists usually take prophylaxis
for malaria and therefore rarely contract malaria. The large discrepancy between
clinical cases and confirmed cases suggest poor clinical diagnosis for malaria
due to lack of facilities and expertise (microscopes and technical staff). However,
it should be noted that the trend of confirmed cases usually closely follows that of
clinical cases (Chirebvu et. al. 1998). Thus, the observation, largely based on
clinical cases, that there are cases of malaria throughout the year suggests that
transmission of malaria is not restricted to the 4 months that other studies
specify. During heavy rains and during high floods most of the health posts are
difficult to reach and therefore delivery of hospital supplies and access to the
health facilities are made difficult. This results in late treatment and the
consequent fatalities. Despite these difficulties there is a malaria control
programme implemented by the Ministry of Health. As indicated above there will
be need to have an HIA if the Shakawe irrigation expansion plans proceed. The
heavy floods experienced in 2009 may result in the Molapo farming (flood-
recession farming) practice being extended to areas which have not received
floods in many years. Thus, malaria transmission may increase as people get
exposed to more mosquito bites due to increased numbers of mosquitoes arising
from the cultivated areas.
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5. CONCLUSIONS
This analysis shows that although there are many potential health hazards
associated with water inflows into the Okavango Delta and rainfall, the hazards
that need to be monitored closely are malaria and schistosomiasis. Monitoring
the malaria situation is likely to be much easier as that can be done in the context
of the existing malaria control programme but monitoring the schistosomiasis
situation is difficult since there is no operational control programme. However,
malnutrition, cholera and diarrheal diseases need to be monitored during periods
of extreme weather events (too much water and too little water) as they interact
with devastating effects. For instance, a malnourished child who ingests a
diarrhea causative agent like Cryptosporidium is likely to die if they do not receive
attention in good time.
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6. RECOMMENDATIONS
Based on the analysis done by reviewing existing literature and use of secondary
data obtained from the Ngamiland Council the following recommendations are
made.
6.1 There is need to strengthen the capacity of health institutions and other
protection agencies in the Delta and riparian areas to deal with malaria. This
can be done by building capacity for diagnosis of malaria through staff
refresher courses and routinely confirming cases either on site or at higher
level.
6.2 Training of staff in health posts on schistosomiasis and advocacy is needed
as there seems to be a lack of attention on the disease.
6.3 There is need to carry out a Delta wide survey (both parasitology and snail
aspects) to determine the current situation of schistosomiasis. This can be
done as an extension of the work currently being done in Maun.
6.4 There is need to improve the water and sanitation facilities in Delta riparian
areas to prevent and/or control diarrheal disease.
6.5 In view of the uncertainty regarding climate change with regards rainfall there
is need to carry out studies that determine the possible impacts of the wet
and dry scenarios of the Okavango Basin on diseases, particularly malaria
and schistosomiasis
22
TDA Botswana Public Health
7. REFERENCES
Andersen, L et al. (1984). Human schistosomiasis in Ngamiland 1983. Botswana
Epidemiological Bulletin 5. 60-86.
Appleton, C.C., Curtis, B.A., Alonso, L.E. and Kipping J. (2000). Freshwater
Invertebrates of the Okavango Delta, Botswana. RAP Bulletin of Biological
Assessment 27. Chapter 4. 58-69.
Central Statistics Office Botswana. (2006). Table 7: Selected notifiable diseases
cases and deaths, 1998-2003.
MARA/ARMA. (2001). Botswana: Duration of malaria transmission season Retrieved
June 4, 2008, from http://www.mara.org.za/pdfmaps/BotSeasonality.PDF
Sibiya, J.B. Community participation and Health Education in Botswana. Tropical
Medicine Parasitology, 37: 168-169.
Rudo, B.M. (1978) Report oon Botswana National Bilharziasis Survey.
Thomson, M. C., Mason, S. J., Phindela, T., & Connor, S. J. (2005). Use of rainfall
and
sea surface temperature monitoring for malaria early warning in Botswana. American
journal of tropical medicine and hygiene, 73(1), 214-221.
World Health Organisation. (2007). Fact sheet No94. Retrieved June 4, 2008, from
http://www.who.int/mediacentre/factsheets/fs094/en/index.html
.
23
TDA Botswana Land Use Planning.
The Okavango River Basin Transboundary Diagnostic Analysis Technical Reports
I
Diagnostic Analysis to establish a base of available
n 1994, the three riparian countries of the Okavango
scientific evidence to guide future decision making.
River Basin Angola, Botswana and Namibia agreed
The study, created from inputs from multi-disciplinary
to plan for collaborative management of the natural
teams in each country, with specialists in hydrology,
resources of the Okavango, forming the Permanent
hydraulics, channel form, water quality, vegetation,
Okavango River Basin Water Commission (OKACOM).
aquatic invertebrates, fish, birds, river-dependent
In 2003, with funding from the Global Environment
terrestrial wildlife, resource economics and socio-
Facility, OKACOM launched the Environmental
cultural issues, was coordinated and managed by a
Protection and Sustainable Management of the
group of specialists from the southern African region
Okavango River Basin (EPSMO) Project to coordinate
in 2008 and 2009.
development and to anticipate and address threats to
the river and the associated communities and
The following specialist technical reports were
environment. Implemented by the United Nations
produced as part of this process and form
Development Program and executed by the United
substantive background content for the Okavango
Nations Food and Agriculture Organization, the project
River Basin Trans-boundary Diagnostic Analysis
produced the Transboundary.
Final Study
Reports integrating findings from all country and background reports, and covering the entire
Reports
basin.
Aylward, B.
Economic Valuation of Basin Resources: Final Report to
EPSMO Project of the UN Food & Agriculture Organization as
an Input to the Okavango River Basin Transboundary
Diagnostic Analysis
Barnes, J. et al.
Okavango River Basin Transboundary Diagnostic Analysis:
Socio-Economic Assessment Final Report
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment Project
C.A.
Initiation Report (Report No: 01/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment EFA
C.A.
Process Report (Report No: 02/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Guidelines for Data Collection, Analysis and Scenario Creation
(Report No: 03/2009)
Bethune,
S.
Mazvimavi,
Okavango River Basin Environmental Flow Assessment
D. and Quintino, M.
Delineation Report (Report No: 04/2009)
Beuster, H.
Okavango River Basin Environmental Flow Assessment
Hydrology Report: Data And Models(Report No: 05/2009)
Beuster,
H. Okavango River Basin Environmental Flow Assessment
Scenario Report : Hydrology (Report No: 06/2009)
Jones, M.J.
The Groundwater Hydrology of The Okavango Basin (FAO
Internal Report, April 2010)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions (Volume 1
of 4)(Report No. 07/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions (Volume 2
of 4: Indicator results) (Report No. 07/2009)
King, J.M. and Brown,
Okavango River Basin Environmental Flow Assessment
C.A.
Scenario Report: Ecological and Social Predictions: Climate
Change Scenarios (Volume 3 of 4) (Report No. 07/2009)
King, J., Brown, C.A.,
Okavango River Basin Environmental Flow Assessment
Joubert, A.R. and
Scenario Report: Biophysical Predictions (Volume 4 of 4:
Barnes, J.
Climate Change Indicator Results) (Report No: 07/2009)
King, J., Brown, C.A.
Okavango River Basin Environmental Flow Assessment Project
and Barnes, J.
Final Report (Report No: 08/2009)
Malzbender, D.
Environmental Protection And Sustainable Management Of The
Okavango River Basin (EPSMO): Governance Review
Vanderpost, C. and
Database and GIS design for an expanded Okavango Basin
Dhliwayo, M.
Information System (OBIS)
Veríssimo, Luis
GIS Database for the Environment Protection and Sustainable
Management of the Okavango River Basin Project
Wolski,
P.
Assessment of hydrological effects of climate change in the
Okavango Basin
Country Reports
Angola
Andrade e Sousa,
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Biophysical Series
Helder André de
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Sedimentologia &
24
TDA Botswana Public Health
Geomorfologia
Gomes, Amândio
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Vegetação
Gomes,
Amândio
Análise Técnica, Biofísica e Socio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango: Relatório
Final:Vegetação da Parte Angolana da Bacia Hidrográfica Do
Rio Cubango
Livramento, Filomena
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina:Macroinvertebrados
Miguel, Gabriel Luís
Análise Técnica, Biofísica E Sócio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango:
Subsídio Para o Conhecimento Hidrogeológico
Relatório de Hidrogeologia
Morais, Miguel
Análise Diagnóstica Transfronteiriça da Bacia do Análise Rio
Cubango (Okavango): Módulo da Avaliação do Caudal
Ambiental: Relatório do Especialista País: Angola Disciplina:
Ictiofauna
Morais,
Miguel
Análise Técnica, Biófisica e Sócio-Económica do Lado
Angolano da Bacia Hidrográfica do Rio Cubango: Relatório
Final: Peixes e Pesca Fluvial da Bacia do Okavango em Angola
Pereira, Maria João
Qualidade da Água, no Lado Angolano da Bacia Hidrográfica
do Rio Cubango
Santos,
Carmen
Ivelize
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Van-Dúnem S. N.
Okavango: Módulo do Caudal Ambiental: Relatório de
Especialidade: Angola: Vida Selvagem
Santos, Carmen Ivelize
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Van-Dúnem S.N.
Okavango:Módulo Avaliação do Caudal Ambiental: Relatório de
Especialidade: Angola: Aves
Botswana Bonyongo, M.C.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Wildlife
Hancock, P.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module : Specialist Report: Country:
Botswana: Discipline: Birds
Mosepele,
K. Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Fish
Mosepele, B. and
Okavango River Basin Technical Diagnostic Analysis:
Dallas, Helen
Environmental Flow Module: Specialist Report: Country:
Botswana: Discipline: Aquatic Macro Invertebrates
Namibia
Collin Christian &
Okavango River Basin: Transboundary Diagnostic Analysis
Associates CC
Project: Environmental Flow Assessment Module:
Geomorphology
Curtis, B.A.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report Country:
Namibia Discipline: Vegetation
Bethune, S.
Environmental Protection and Sustainable Management of the
Okavango River Basin (EPSMO): Transboundary Diagnostic
Analysis: Basin Ecosystems Report
Nakanwe, S.N.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia: Discipline: Aquatic Macro Invertebrates
Paxton,
M. Okavango River Basin Transboundary Diagnostic Analysis:
Environmental Flow Module: Specialist
Report:Country:Namibia: Discipline: Birds (Avifauna)
Roberts, K.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia: Discipline: Wildlife
Waal,
B.V. Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module: Specialist Report: Country:
Namibia:Discipline: Fish Life
Country Reports
Angola
Gomes, Joaquim
Análise Técnica dos Aspectos Relacionados com o Potencial
Socioeconomic
Duarte
de Irrigação no Lado Angolano da Bacia Hidrográfica do Rio
Series
Cubango: Relatório Final
Mendelsohn,
.J.
Land use in Kavango: Past, Present and Future
Pereira, Maria João
Análise Diagnóstica Transfronteiriça da Bacia do Rio
Okavango: Módulo do Caudal Ambiental: Relatório do
Especialista: País: Angola: Disciplina: Qualidade da Água
Saraiva, Rute et al.
Diagnóstico Transfronteiriço Bacia do Okavango: Análise
Socioeconómica Angola
25
TDA Botswana Public Health
Botswana Chimbari, M. and
Okavango River Basin Trans-Boundary Diagnostic Assessment
Magole, Lapologang
(TDA): Botswana Component: Partial Report: Key Public Health
Issues in the Okavango Basin, Botswana
Magole,
Lapologang
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Land Use Planning
Magole, Lapologang
Transboundary Diagnostic Analysis (TDA) of the Botswana p
Portion of the Okavango River Basin: Stakeholder Involvement
in the ODMP and its Relevance to the TDA Process
Masamba,
W.R.
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Output 4: Water Supply and
Sanitation
Masamba,W.R.
Transboundary Diagnostic Analysis of the Botswana Portion of
the Okavango River Basin: Irrigation Development
Mbaiwa.J.E. Transboundary Diagnostic Analysis of the Okavango River
Basin: the Status of Tourism Development in the Okavango
Delta: Botswana
Mbaiwa.J.E. &
Assessing the Impact of Climate Change on Tourism Activities
Mmopelwa, G.
and their Economic Benefits in the Okavango Delta
Mmopelwa,
G.
Okavango River Basin Trans-boundary Diagnostic Assessment:
Botswana Component: Output 5: Socio-Economic Profile
Ngwenya, B.N.
Final Report: A Socio-Economic Profile of River Resources and
HIV and AIDS in the Okavango Basin: Botswana
Vanderpost,
C.
Assessment of Existing Social Services and Projected Growth
in the Context of the Transboundary Diagnostic Analysis of the
Botswana Portion of the Okavango River Basin
Namibia
Barnes, J and
Okavango River Basin Technical Diagnostic Analysis:
Wamunyima, D
Environmental Flow Module: Specialist Report:
Country: Namibia: Discipline: Socio-economics
Collin Christian &
Technical Report on Hydro-electric Power Development in the
Associates CC
Namibian Section of the Okavango River Basin
Liebenberg, J.P.
Technical Report on Irrigation Development in the Namibia
Section of the Okavango River Basin
Ortmann, Cynthia L.
Okavango River Basin Technical Diagnostic Analysis:
Environmental Flow Module : Specialist Report Country:
Namibia: discipline: Water Quality
Nashipili,
Okavango River Basin Technical Diagnostic Analysis: Specialist
Ndinomwaameni
Report: Country: Namibia: Discipline: Water Supply and
Sanitation
Paxton,
C.
Transboundary Diagnostic Analysis: Specialist Report:
Discipline: Water Quality Requirements For Human Health in
the Okavango River Basin: Country: Namibia
26
TDA Botswana Land Use Planning.
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