Taenia solium cysticercosis in Eastern and Southern Africa: an emerging problem in agriculture and public health

Pig production has increased tremendously in Eastern and Southern Africa (ESA), particularly in smallholder rural communities. The increase in pig production has mainly been due to land scarcity, increase in pork consumption in many areas including urban centers, and the recognition by many communities of the fast and greater return of the pig industry, compared with other domesticated livestock industries. Concurrent with the increase in smallholder pig keeping and pork consumption, there have been increasing reports of Taenia solium cysticercosis in pigs and humans in the ESA region, although the problems are under-recognized by all levels in many ESA countries. Having recognizing this, scientists researching T. solium in ESA formed a regional cysticercosis working group (CWGESA) to increase awareness of the problem and enable effective and sustainable control of T. solium. This article summarizes the status of T. solium infections in humans and pigs in the ESA countries and highlights the formation and progress of the CWGESA

Targeting the Wolbachia Cell Division Protein FtsZ as a New Approach for Antifilarial Therapy

Filarial nematode parasites are responsible for a number of devastating diseases in humans and animals. These include lymphatic filariasis and onchocerciasis that afflict 150 million people in the tropics and threaten the health of over one billion. The parasites possess intracellular bacteria, Wolbachia, which are needed for worm survival. Clearance of these bacteria with certain antibiotics leads to parasite death. These findings have pioneered the approach of using antibiotics to treat and control filarial infections. In the present study, we have investigated the cell division process in Wolbachia for new drug target discovery. We have identified the essential cell division protein FtsZ, which has a GTPase activity, as an attractive Wolbachia drug target. We describe the molecular characterization and catalytic properties of the enzyme and demonstrate that the GTPase activity is inhibited by the natural product, berberine, and small molecule inhibitors identified from a high-throughput screen. We also found that berberine was effective in reducing motility and reproduction in B. malayi parasites in vitro. Our results should facilitate the discovery of selective inhibitors of FtsZ as a novel antibiotic approach for controlling filarial infection

Heart disease among children with HIV/AIDS attending the paediatric infectious disease clinic at Mulago Hospital

BACKGROUND: There are very few published studies of heart disease in HIV infected children living in sub-Saharan Africa, a region with more than 50% of the world's population of HIV infected patients. OBJECTIVES: To determine the prevalence, and describe the type and clinical presentation of heart disease among children with HIV attending an ambulatory clinic. METHODOLOGY: Two hundred and thirty (230) HIV infected children attending the Paediatric Infectious Disease Clinic at Mulago hospital were recruited by simple random sampling in a cross-sectional study. The children were evaluated clinically, and investigated by electrocardiography and echocardiography. RESULTS: Thirty-two children (13.9%) had asymptomatic HIV disease, 156 (67.8%) had AIDS related complex while 42 (18.3%) had AIDS. Heart abnormalities were detected in 51% of the children (40.0% by echocardiography alone and 26.5% by electrocardiography alone). Heart abnormalities were most prevalent in children with AIDS (76.2%) and least prevalent in children with asymptomatic HIV disease (25.0%). The abnormalities included; Sinus tachycardia (21%), left ventricular systolic dysfunction (17%), right ventricular dilatation (14%), congenital heart disease (4.8%), dilated cardiomyopathy (3.0%), pericarditis (2.2%) and cor pulmonale (1.3%). Children with left ventricular systolic dysfunction significantly had easy fatigability, dyspnoea on exertion and tachypnoea. Other heart abnormalities presented with non-specific clinical features. CONCLUSIONS: Heart abnormalities were common especially in children with symptomatic HIV disease and included sinus tachycardia, left ventricular systolic dysfunction and right ventricular dilatation. The detected heart abnormalities, except left ventricular systolic dysfunction, had non-specific clinical features

The immunological relationship between Typanosoma evansi and Trypanosoma vivax: Immunization by infection, treatment and challenge findings

Trypanosoma evansi and Trypanosoma vivax show very high cross-reactivity in serology; and previous serum neutralization studies demonstrated that anti T. evansi serum contained lytic antibodies that could lyse a large proportion of T. vivax trypomastigotes though anti T. vivax serum had no effect on T. evansi trypomastigotes. This supports the suspicion that the two parasite species are immunologically closely related and prior infection with one species could cross protect against infection with the other species. The possibility of mice infected with T. evansi then treated and challenged with T. vivax being protected against the latter parasite infection and vice versa was investigated. Mice were infected with T. evansi, then treated with Diminasan after the infection had become patent and challenged with T. vivax and vice versa. The challenged mice were monitored for patent infection through examination of their tail blood to establish whether there was any cross protection. Mice were also infected, treated and challenged with homologous trypanosome species to establish whether there was any protection after prior infection followed by treatment and homologous challenge. Mice without prior infection but treated then challenged and those without prior infection and not treated but challenged were included as unexposed and Deminasan controls, respectively. The mean survival time of the Deminasan control mice was not significantly different (p = 0.246183 > 0.05) from the mean survival time of the unexposed control mice. However, mice previously exposed to T. evansi infection then challenged with T. vivax had a significantly higher mean survival time (p = 0.022055 < 0.05) compared to the unexposed control mice. Similarly the mean survival times of mice without prior exposure to T. vivax infection but treated then challenged with T. evansi (unexposed control) and those without prior infection and not treated but challenged (Deminasan control) were not significantly different (p = 0.122966 > 0.05). The mean survival time of mice previously exposed to T. vivax infection then challenged with T. evansi was significantly higher compared to the mean survival times of the unexposed and Deminasan control mice (p = 0.01622< 0.05). Previous exposure to T. evansi infection followed by treatment and homologous challenge conferred 50% protection to mice previously infected with T. evansi then treated and challenges with T. evansi. While previous exposure to T. vivax infection followed by treatment and homologous challenge only prolonged the mean survival time of mice previously infected with T. vivax then treated and challenged with T. vivax.The above findings, therefore, suggest that T. evansi and T. vivax are immunologically related and prior infection with one species prolongs the survival time of mice previously infected with one species when challenged with the other. Previous exposure to T. evansi infection followed by homologous challenge confers 50% protection to mice previously exposed to T. evansi infection. While previous exposure to T. vivax infection followed by homologous challenge only prolongs the mean survival time of mice previously exposed to T. vivax infection.Keywords: Immunological relationship, T. evansi, T. vivax, cross protectio

In Vitro Trypanocidal Activity of Antibodies to Bacterially Ex­pressed Trypanosoma brucei Tubulin

Background: There are only four drugs for treating African trypanosomiasis, a devastating disease in sub-Saharan Africa. With slow discovery of better drugs, vaccination is viewed as the best method of control. We previously showed that antibodies to native Trypanosoma brucei brucei tubulin inhibit the growth of trypanosomes in culture. Here, we aimed to determine the effect of antibodies to bacte­rially expressed trypanosome tubulin on T. brucei brucei growth. Methods: T. brucei brucei alpha and beta tubulin genes were individually expressed in Escherichia coli under the tryptophan promoter. Monoclonal tubulin antibodies reacted specifically with the ex­pressed tubulins with no cross-reaction with the opposite tubulin. Rabbits were immunized with 450μg each of the concentrated recombinant tubulin, and production of antibodies assessed by ELISA and Western blotting. The effect of polyclonal antibodies on trypanosome growth was deter­mined by culturing bloodstream T. brucei brucei in up to 25% of antisera. Results: Low antisera dilutions (25%) from the immunized rabbits inhibited trypanosome growth. The most cytotoxic antisera were from one rabbit immunized with a mixture of both alpha and beta tubulins. However, the result was not reproduced in other rabbits and there was no apparent effect on growth at higher antisera dilutions. Conclusion: Antibodies to bacterially expressed trypanosome tubulin are not effective at killing cul­tured bloodstream trypanosomes

Application of a reverse line blot assay to the study of haemoparasites in cattle in Uganda

Recent advances in genomic technology have focused many veterinary researchers on the possibility of producing one multivalent recombinant vaccine against all the haemoparasites that infect cattle in the tropics. Before such a vaccine is developed it is essential to define target cattle populations as well as the range of anti-pathogen vaccines required in order to control disease. To further this objective, we have evaluated a reverse line blot (RLB) assay, which simultaneously detects the principal tick transmitted protozoan and rickettsial cattle pathogens, in different epidemiological scenarios in Uganda. A critical question is the sensitivity, particularly in relation to detecting carrier animals. As Theileria parva is considered to be the most important pathogen in the region, we assessed the sensitivity of the RLB assay for T. parva and showed that 1–2×103 parasites per ml of blood could be detected—a level comparable with previously developed PCR methods and well below conventional microscopic detection. We applied the RLB assay to evaluate the differences in pathogen profiles between crossbred and indigenous cattle and show that there were different profiles, with a low prevalence of T. parva and Theileria taurotragi in the indigenous cattle compared to a high prevalence in the crossbred cattle. In contrast, we show higher prevalences of Theileria mutans and Theileria velifera in the indigenous compared to the crossbred cattle. Interestingly Anaplasma marginale, Babesia bovis and Babesia bigemina were of low prevalence but a high prevalence of Ehrlichia bovis was seen, raising the question of whether this rickettsial species could be pathogenic in cattle. Analysis of animals with clinical symptoms of East Coast Fever showed that, while T. parva is a major cause of these symptoms, T. mutans and possibly T. taurotragi and T. velifera, may also cause clinical disease. Overall, the results presented here highlight the complexity of tick-borne pathogen infections in cattle in Uganda

Immunodiagnostic potential of a 27 kDa protein of Fusarium xylarioides, the cause of coffee wilt disease in Robusta coffee in Uganda

Several Fusarium species infect Robusta coffee; these Fusarium xylarioides Steyaert (Gibberella xylarioides Heim and Saccas) are the most virulent and responsible for the destructive Robusta coffee wilt disease in Uganda. To date, F. xylarioides has not been isolated directly from soil, though the pathogen can persist in soil for a short time. In this study, a promising diagnostic target which can be developed into a serological test for F. xylarioides in coffee plants and soil has been identified and validated for identification. Water-soluble extracts of mycelia from six Fusaruim species were resolved by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The different protein profiles from the other five Fusarium species were compared and contrasted with that of F. xylarioides. Protein bands that appeared peculiar to F. xylarioides were cut and injected into rabbits to produce polyclonal antibodies. Dot blot and Western blot analyses showed one immunodominant antigen (27 kDa) common to all F. xylarioides isolates analyzed. No cross-reactivity of anti-27 kDa antibodies were observed in the entire test Fusarium species. The results suggest that polyclonal antibodies raised against the endoantigens from F. xylarioides of 27 kDa, is a promising tool for the rapid, sensitive, and accurate detection of pathogen in soil and plant parts.Keywords: Gibberella xylarioides, coffee wilt disease, antigen, antibodies, Uganda.African Journal of Biotechnology, Vol 13(29) 2922-292