Michael Ocaido

Echinococcosis in sub-Saharan Africa: emerging complexity.

Cystic echinococcosis occurs in most regions of sub-Saharan Africa, but the frequency of this zoonosis differs considerably among and within countries. Especially human cases seem to be focally distributed. A number of environmental and behavioural factors partially explain this pattern, i.e. density of livestock, presence of dogs, uncontrolled slaughter, and hygiene. In addition, the various taxa of Echinococcus spp. are known to differ considerably in infectivity to different host species including humans. Genetic characterizations of isolates, which are necessary to evaluate the impact of this factor - so far done in only a few countries - indicate that the diversity of Echinococcus spp. in Sub-Saharan Africa is greater than on any other continent. The very incomplete data which are available show that sympatrical taxa may infect different hosts, others may be geographically restricted, some life cycles involve livestock, others wild animals. Possible implications of this complexity for public health, livestock economy and conservation are briefly discussed.

Cystic echinococcosis in sub-Saharan Africa

Cystic echinococcosis is regarded as endemic in sub-Saharan Africa; however, for most countries only scarce data, if any, exist. For most of the continent, information about burden of disease is not available; neither are data for the animal hosts involved in the lifecycle of the parasite, thus making introduction of preventive measures difficult. Available evidence suggests that several species or strains within the Echinococcus granulosus complex are prevalent in sub-Saharan Africa and that these strains might be associated with varying virulence and host preference. Treatment strategies (chemotherapy, percutaneous radiological techniques, but mainly surgery) predominantly target active disease. Prevention strategies encompass anthelmintic treatment of dogs, slaughter hygiene, surveillance, and health-educational measures. Existing data are suggestive of unusual clinical presentations of cystic echinococcosis in some parts of the continent, for which the causes are speculative.

Risk factors, perceptions and practices associated with Taenia solium cysticercosis and its control in the smallholder pig production systems in Uganda: a cross-sectional survey.

BackgroundPrevalence studies report Taenia solium cysticercosis in pig and human populations in Uganda. However, the factors influencing occurrence in smallholder pig production systems are not well documented and little is known about farmers’ perceptions of T. solium cysticercosis or farmer practices that could reduce transmission.MethodsTo determine the risk factors, perceptions and practices regarding T. solium cysticercosis, a household survey using a semi-structured questionnaire was conducted in 1185 households in the rural and urban pig production systems in Masaka, Mukono and Kamuli Districts. Logistic regression was used to measure associations of risk factors with infection. Performance scores were calculated to summarise perceptions and practices of farmers regarding taeniosis, human cysticercosis and porcine cysticercosis as well as farmer behavior related to control or breaking transmission.ResultsPig breed type, farmers’ knowledge about transmission, sources of water used, and pig keeping homes where family members were unable to use the latrine were all significantly associated with T. solium cysticercosis in pigs. Performance scores indicated that farmers were more aware of taeniosis (63.0%; 95% Confidence Interval 60.0-65.8) than human or porcine cysticercosis; only three farmers (0.3%, 95% CI = 0.1–0.8) had knowledge on all three conditions. More farmers reported that they dewormed pigs (94.1%) than reported deworming themselves and their family members (62.0%). Albendazole was the most commonly used drug for deworming both pigs and humans (85.0 and 81.5% respectively). Just over half (54.6%) of the farmers interviewed had clean water near the latrines for washing hands. Of these, only 41.9% used water with soap to wash hands after latrine use.ConclusionFactors that significantly influenced occurrence of T. solium cysticercosis in pigs were identified. Farmers had some knowledge about the disease but did not link taeniosis, human cysticercosis, and porcine cysticercosis. Therefore, there is need to employ strategies that raise awareness and interrupt transmission.

Economic impact of ticks and tick-borne diseases on cattle production systems around Lake Mburo National Park in South Western Uganda

A longitudinal economic impact study of Ticks and Tick-Borne Diseases (TTBDs) in cattle around Lake Mburo National Park (LMNP) was done. Impact was valued using Uganda Shilling (Ug. Shs) (exchange rate of 1USD to Ug. Shs 1,420). The costs for controlling TTBDs was constituting 85.6 ± 3.2% (pastoral) and 73.8 ± 4.2% (ranches) to total disease control costs. The main costs were on tick control, constituting 83.1% (ranches) and 87.9% (pastoral). In pastoral herds, the costs were negatively correlated to herd size (r = −0.99). The mean annual cost per cattle for controlling TTBDs for ranch and pastoral herds was similar Ug. Shs 5,900 ± 545. The mean annual Economic Cost (EC) of TTBDs per cattle was not significantly different (p > 0.05) between pastoral (Ug. Shs 6,700 ± 580) and ranch herds (Ug. Shs 7,600 ± 970). The mean annual EC per cattle was negatively correlated (r = −0.99) with herd size in pastoral systems contrary to positive correlation (r = 0.99) observed among the ranches. The major component of EC of TTBDs of 88.2% (pastoral) and 78.6% (ranches) was due to their control. The other component was owed to mortality, which was positively correlated (p < 0.01) to the ranch herd size. The total annual EC of TTBDs around LMNP was Ug. Shs 437,754,600 (USD 308,144).

An up-date on the prevalence of sickle cell trait in Eastern and Western Uganda

BackgroundThe first survey on sickle cell disease (SCD) done in Uganda in 1949, reported the district of Bundibugyo in Western Uganda to have the highest sickle cell trait (SCT) prevalence (45%). This is believed to be the highest in the whole world. According to the same survey, the prevalence of SCT in the districts of Mbale and Sironko in the East was 20-28%, whilst the districts of Mbarara and Ntungamo in the West had 1-5%. No follow-up surveys have been conducted over the past 60 years. SCA accounts for approximately 16.2% of all pediatric deaths in Uganda. The pattern of SCT inheritance, however, predicts likely changes in the prevalence and distribution of the SCT. The objective of the study therefore was to establish the current prevalence of the SCT in Uganda.MethodsThis study was a cross sectional survey which was carried out in the districts of Mbale and Sironko in the Eastern, Mbarara/Ntungamo and Bundibugyo in Western Uganda. The participants were children (6 months-5 yrs). Blood was collected from each subject and analyzed for hemoglobin S using cellulose acetate Hb electrophoresis.ResultsThe established prevalence of the SCT (As) in Eastern Uganda was 17.5% compared to 13.4% and 3% in Bundibugyo and Mbarara/Ntungamo respectively. 1.7% of the children in Eastern Uganda tested positive for haemoglobin ss relative to 3% in Bundibugyo, giving gene frequencies of 0.105 and 0.097 for the recessive gene respectively. No ss was detected in Mbarara/Ntungamo.ConclusionsA shift in the prevalence of the SCT and ss in Uganda is notable and may be explained by several biological and social factors. This study offers some evidence for the possible outcome of intermarriages in reducing the incidence of the SCT.

Socio-economic factors influencing the use of acaricides on livestock: a case study of the pastoralist communities of Nakasongola District, Central Uganda

A study was conducted in Nakasongola district to determine socioeconomic factors that influence the use of acaricides on livestock. The information was got through focus group discussions (FGDs) and use of a questionnaire. Questionnaire was administered to one hundred households. Acaricides were used to kill ticks and biting flies which transmit diseases and cause discomfort to livestock. But to a less extent was also done for cosmetic purposes. Most of the farmers were aware of the correct acaricide dilutions as recommended by the manufacturers but they ignored them. But through trial and error came up with their own dilutions, which they said were very cost-effective. Further, they experimented on concoctions of different acaricide mixes and came up with acaricide combinations which were more effective in killing ticks and flies. Veterinarians and acaricide manufacturing companies had called this a malpractice. On the contrary, this should be treated as an innovation by farmers in their endeavour to find a cheaper sustainable method of controlling ticks and flies. Further research should therefore be done on these working “malpractices”.

Disease incidence in ranch and pastoral livestock herds around Lake Mburo National Park, in South Western Uganda

A longitudinal study was done to monitor incidence of livestock diseases in ranch and pastoral herds around Lake Mburo National Park, in South-western Uganda with a high level of wildlife (impala and zebra) and livestock (cattle and goats) interactions. East Coast Fever (ECF), abortions, helminthosis and starvation due to drought were major livestock disease problems encountered. ECF was a major disease affecting mainly calves, causing mortality both in ranch (8.5%) and pastoral (8.2%) herds. Meanwhile, drought was a more serious in pastoral than ranch herds (p < 0.05), killing 28.5 % and 5.8% of adult female cattle in respective production systems. Other endemic diseases found and controlled by vaccination were FMD, CBPP and blackquarter. In both cattle and goats helminthosis was causing mortalities, 3.3% and 0.8% among calves in pastoral and ranches respectively; and 4.8% and 6.9% among kids and sub-adult goats respectively. Many cases of abortions occurred among pastoral herds. In conclusion, the disease incidence among livestock was the same or relatively low as compared to other areas without wildlife.

Enhancing knowledge and awareness of biosecurity practices for control of African swine fever among smallholder pig farmers in four districts along the Kenya-Uganda border.

A study was undertaken along the Kenya–Uganda border in four districts of Tororo and Busia (Uganda) and Busia and Teso (Kenya) to understand smallholder farmers’ knowledge, practices and awareness of biosecurity measures. Information was collected by administering questionnaires to 645 randomly selected pig households in the study area. In addition, focus group discussions were carried out in 12 villages involving 248 people using a standardized list of questions. The outcome suggested that there was a very low level of awareness of biosecurity practices amongst smallholder farmers. We conclude that adoption of specific biosecurity practices by smallholder farmers is feasible but requires institutional support. There is a clear requirement for government authorities to sensitize farmers using approaches that allow active participation of farmers in the design, planning and implementation of biosecurity practices to enable enhanced adoption.

Prevalence of pathogenic free-living amoeba and other protozoa in natural and communal piped tap water from Queen Elizabeth protected area, Uganda

BackgroundPathogenic water dwelling protozoa such as Acanthamoeba spp., Hartmannella spp., Naegleria spp., Cryptosporidium spp. and Giardia spp. are often responsible for devastating illnesses especially in children and immunocompromised individuals, yet their presence and prevalence in certain environment in sub-Saharan Africa is still unknown to most researchers, public health officials and medical practitioners. The objective of this study was to establish the presence and prevalence of pathogenic free-living amoeba (FLA), Cryptosporidium and Giardia in Queen Elizabeth Protected Area (QEPA).MethodsSamples were collected from communal taps and natural water sites in QEPA. Physical water parameters were measured in situ. The samples were processed to detect the presence of FLA trophozoites by xenic cultivation, Cryptosporidium oocysts by Ziehl-Neelsen stain and Giardia cysts by Zinc Sulphate floatation technique. Parasites were observed microscopically, identified, counted and recorded. For FLA, genomic DNA was extracted for amplification and sequencing.ResultsBoth natural and tap water sources were contaminated with FLA, Cryptosporidium spp. and Giardia spp. All protozoan parasites were more abundant in the colder rainy season except for Harmannella spp. and Naegleria spp. which occurred more in the warmer months. The prevalence of all parasites was higher in tap water than in natural water samples. There was a strong negative correlation between the presence of Acanthamoeba spp., Hartmannella spp., Cryptosporidium spp. and Giardia spp. with Dissolved Oxygen (DO) (P < 0.05). The presence of Cryptosporidium spp. showed a significant positive correlation (P < 0.05) with conductivity, pH and Total Dissolved Solids (TDS); whereas the presence of Giardia spp. had only a strong positive correlation with TDS. Molecular genotyping of FLA produced 7 Acanthamoeba, 5 Echinamoeba, 2 Hartmannella, 1 Bodomorpha, 1 Nuclearia and 1 Cercomonas partial sequences.ConclusionsAll water collection sites were found to be contaminated with pathogenic protozoa that could possibly be the cause of a number of silent morbidities and mortalities among rural households in QEPA. This implies that water used by communities in QEPA is of poor quality and predisposes them to a variety of protozoan infections including the FLA whose public health importance was never reported, thus necessitating adoption of proper water safety measures.

Solubility tests and the peripheral blood film method for screening for sickle-cell disease: A cost benefit analysis

Objective . To determine the cost benefit of screening for sicklecell disease among infants at district health centres in Uganda using sickling, solubility tests and the peripheral blood film method. Methods . Pilot screening services were established at district health centres. Cost benefit analysis (CBA) was performed in four scenarios: A1 – where there are no sickle-cell screening services at district health centres and all children are referred either to Mulago national referral hospital or A2 – a regional hospital for haemoglobin (Hb) electrophoresis; B1 – when there are screening services at district health centres, only positive samples are taken either to Mulago Hospital or B2 – the regional hospital for confirmation using haemoglobin electrophoresis. Calculations were done in Uganda shillings (USh). Results . Initial operational costs were high for all scenarios but variably reduced in the subsequent years. Scenarios A1 and A2 were very sensitive compared with B1 and B2. Scenario A1 had the highest screening costs in the subsequent years, costing over 62 000 USh per test in both eastern and western Uganda. Scenario B2 was sensitive and cheaper when using the sickling test, but was expensive and insensitive when using the solubility test and more insensitive though cheaper when using the peripheral blood film method. Conclusions and recommendatio n. Screening children in Mulago hospital using haemoglobin electrophoresis (A1) was very expensive although it was sensitive. Screening the children at four health centres using the sickling method and confirming positive samples at a regional hospital (B2) was both cheap and sensitive and is therefore recommended