First report of Mycobacterium bovis in wild chacma baboons (Papio ursinus) at the human-wildlife interface area in Zambia.

Mycobacterium bovis (M. bovis) causes tuberculosis in mammals and is a major public health threat worldwide. While M. bovis has been reported in humans, domestic and wild ruminants at the human-wildlife-livestock interface area in Zambia, there is paucity of information on the role of primates as reservoir hosts. We screened seven wild chacma baboons (Papio ursinus) for tuberculosis at the human-wildlife interface area in Lochinvar National Park in the Kafue Flats, Zambia. Following necropsy, lung tissue and associated lymph nodes with tuberculous-like lesions collected from four adult male baboons were prepared for Mycobacterium culture. The isolates were initially typed using the Mycobacterium tuberculosis complex-discrimination multiplex PCR assay and further characterized by spoligotyping and 26-loci MIRU-VNTR. Mycobacteria were isolated from all four animals and identified as M. bovis by PCR. On Spoligotyping, all isolates belonged to SB 0120 spoligotype, which is similar to what was previously reported in humans, cattle and Kafue lechwe antelopes in Kafue Flats ecosystem. Furthermore, on MIRU-VNTR typing, the baboon isolates clustered with cattle and Kafue lechwe isolates from the same catchment area. This finding intimates probable cross-species transmission of M. bovis in the Kafue Flats ecosystem. Due to the close interaction of baboons and humans at interface areas in Zambia, our results have potential implications for public health. Equally, this finding raises concerns for conservation.

Brucella Seroprevalence and Associated Risk Factors in Occupationally Exposed Humans in Selected Districts of Southern Province, Zambia.

Background: Brucellosis is a neglected debilitating zoonosis widely recognized as an occupational health hazard. The seroprevalence of human anti-Brucella antibodies in high-risk populations, as well as their risk factors, have not been well-documented in Zambia. This study aimed at estimating the Brucella seroprevalence in herdsmen and abattoir workers and assess the associated risk factors. Methods: A cross-sectional seroepidemiological study was carried out between May and December 2020 among abattoir workers and herdsmen in Namwala, Monze and Choma districts of Southern Province in Zambia. Seroprevalence was assessed by indirect enzyme-linked immunosorbent assay (i-ELISA) or competitive enzyme-linked immunosorbent assay (c-ELISA) while a questionnaire was administered to obtain epidemiological data. Results: A total of 153 individuals were recruited in the study. The overall Brucella seroprevalence was 20.3% (95% CI: 14.6-27.5). Seropositivity among herdsmen and abattoir workers was 14.4% (95% CI: 9.2-21.8) and 46.4%, (95% CI: 28.8-65.0), respectively. Comparable seropositive results among districts showed Namwala with 26.9%, which was the highest, seconded by Monze 19.0%, and the least was Choma with 11.36%, seropositivity. The multivariate logistic regression model showed that occupation, age category, and district of residence were predictors of being seropositive to Brucella spp. antibodies. The odds of abattoir workers being seropositive to Brucella antibodies were 8.6 (95% CI: 2.6-28.2) higher than that of herdsmen being the reference group. The odds of age category 17-50 years being seropositive to Brucella antibodies were 7.0 (95% CI: 0.7-72.2) higher than being <16 years as the reference group. The odds of one having attained primary level of education being seropositive to Brucella were 1.3 (95% CI: 0.1-14.7) or secondary level of education were 6.2 (95% CI: 0.5-72.6) or tertiary level of education were 5.1 (95% CI: 0.2, 113.3) higher than that of no level of education as the reference group. Furthermore, the odds of a respondent being seropositive to Brucella antibodies were 4.5 (95% CI: 1.3-15.7) for Namwala and 4.9 (95% CI: 1.1-21.7) for Monze higher than that of Choma as the reference group. Conclusion: Anti-Brucella antibodies are prevalent among herdsmen and abattoir workers in the study areas of Zambia (20.26%), a sign of exposure to Brucella pathogens. Type of profession, age and level of education seem to influence the exposure to Brucella pathogens. This zoonosis should be considered as one of the differential diagnosis in humans presenting intermittent fever, malaria-like signs and general pain in humans.

Documenting the absence of bovine brucellosis in dairy cattle herds in the southern region of Malawi and the associated knowledge, attitudes and practices of farmers.

There is paucity of Brucella prevalence data in Malawi. For this reason, a cross-sectional study was conducted, from 06 January 2020 to 27 February 2020, to estimate the seroprevalence of brucellosis in dairy cattle herds amongst smallholder farmers, government and private dairy farms in the southern region. A total of 529 serum samples were screened for anti-Brucella antibodies using the Rose Bengal test (RBT) and a competitive enzyme-linked immunosorbent assay (cELISA). A pre-tested electronic (Epicollect tool, Wellcome Sanger Institute, United Kingdom) questionnaire was administered to 378 smallholder farmers to assess their knowledge, attitudes and practices towards brucellosis. Descriptive statistics were used to analyse the data in Microsoft Excel® and Statistical Package for Social Sciences (SPSS®) version 21. No animal tested positive for presence of anti-Brucella antibodies, indicating 0% prevalence (individual and herd levels). The majority (94.2%; 95% confidence interval [CI]: 91.8-96.5) of smallholder farmers had never heard about brucellosis. Furthermore, assisting during parturition without protective equipment (41.3%; 95% CI: 36.3-46.2) and using bulls for breeding (75%; 95% CI: 70.2-78.9) were amongst the common risk practices that were identified. We could not detect brucellosis in this study that indicates the disease could be very rare or even absent in the dairy cattle herds of the southern region of Malawi. However, further Brucella studies need to be conducted in cattle, small livestock, wildlife and humans to document the true status of brucellosis in the country. Brucellosis surveillance, monitoring, awareness and preventive measures are required to maintain this favourable situation.

Seroprevalence and Risk Factors Associated with Brucella Infection in Camels in the Puntland State of Somalia.

Brucellosis is an important zoonotic disease caused by members of the genus Brucella. Camel brucellosis has been reported in almost all camel-rearing countries in Africa and Asia. A cross-sectional study was conducted between February 2020 and February 2021 in Galkayo, Garowe, and Bosaso districts in the Puntland State of Somalia to investigate the seroprevalence and risk factors of brucellosis in camels. A competitive enzyme-linked immunosorbent assay (c-ELISA) was used to detect anti-Brucella antibodies, while a structured questionnaire was used to collect epidemiological data. A total of 441 camel sera were screened against Brucella antibodies. Thirty-one (7%; 95% CI: 4.8-9.8%) samples were positive, and thirteen (54.2%; 95% CI: 32.8-74.4%) out of the twenty-four farms sampled had at least one seropositive animal. Galkayo district had the highest number of Brucella-seropositive camels (10.3%), followed by Bosaso district (8.6%), while Garowe district had the lowest number of seropositive camels (1.4%). The binary logistic regression model revealed that camels in Galkayo district (p = 0.015; OR: 9.428; 95% CI: 1.539-57.755), camels from large herd sizes of >50 animals (p = 0.019; OR: 5.822; 95% CI: 1.336-25.371), and those in contact with small ruminants (p = 0.011; OR: 10.941; 95% CI: 1.728-69.285) were significantly associated with seropositive cases of camel brucellosis in the Puntland State of Somalia. The present study shows that Brucella infections in camels are prevalent in the three districts covered by the study. This poses a public health risk, because milk from these camels is used for human consumption. Studies focusing on the isolation of Brucella strains in camels and investigating brucellosis in ruminants and humans are recommended in the study area. Validation of serological tests-including c-ELISA-for Brucella antibody detection in camels is also needed.

Seroprevalence of Bovine Brucellosis in Selected Districts of Zambia.

Brucellosis is an infectious zoonosis that has huge economic and public health implications globally. The disease is prevalent in humans, livestock and wildlife in Sub-Saharan Africa. A cross-sectional study was conducted between 6 May 2017 and 31 July 2020 during which 1712 sera from 175 cattle herds in five districts from Southern, Western and Eastern Provinces of Zambia were collected and screened against brucellosis. The Rose Bengal Test (RBT) and competitive Enzyme-linked Immuno Assay (c-ELISA) were used in serial testing for the detection of antibodies against Brucella species. A total of 127 animals from 37 herds tested positive, giving overall individual animal and herd-level seroprevalences of 7.53% (95% CI: 6.28-8.78%) and 21.14% (95% CI: 15.0-27.2%), respectively. Namwala district had the highest herd seroprevalence (33.9%, 95% CI: 21.6-46.1%), while Lundazi did not record any seropositivity. Comparably, Southern Province had the highest individual animal (8.97%, 95% CI: 7-11%) and herd-level (28.5%, 95% CI: 20.3-36.7%) seroprevalences, although this was not statistically significant. Within Southern Province, higher seropositivity was observed in Namwala district (OR: 8.55; CI: 2.66-27.44), among female animals (OR: 2.48; CI: 1.38-4.46) and in those aged 11 years and above (OR: 2.67; CI: 1.34-5.34) as well as in gravid cows (OR: 4.34; CI: 2.08-8.92). Seropositivity was also observed among some animals with hygromas (OR: 6.5; CI: 0.45-94.08) and those with a history of abortion (OR: 1.13; CI: 0.18-7.28) although the findings were not statistically significant. Brucella seroprevalence among traditional cattle in Zambia remains high. Control programs against bovine brucellosis must be introduced to reduce its impact on human health and animal production.

Molecular characterization of Brucella species detected in humans and domestic ruminants of pastoral areas in Kagera ecosystem, Tanzania.

Brucellosis is a zoonotic disease of importance to both public health and the livestock industry. The disease is likely to be endemic in Tanzania and little is reported on molecular characterization of Brucella species in pastoral settings. This study aimed at characterizing Brucella species (targeting genus Brucella) infecting humans, cattle and goat in Kagera region (Ngara and Karagwe districts) using real-time PCR, PCR amplification of 16S rRNA genes and Sanger sequencing. Brucella spp. were detected in 47 samples (19 sera and 28 milk) out of 125 samples (77 sera, 35 milk and 13 aborted materials) using real-time PCR. All aborted materials (13 samples) were negative to real-time PCR. Out of the 47 real-time PCR positive samples (28 milk and 19 sera), 20 samples (10 milk and 10 sera) showed an expected 16S rRNA gene PCR product. Sequence analysis and blasting confirmed the presence of Brucella spp. in pastoral areas of Kagera region. The Brucella spp. from Kagera were phylogenetically grouped in two clades and three branches all closer to B. melitensis, B. abortus and B. suis from USA, Sudan and Iran. However, they were distinct from other species isolated also in USA, New Zealand, Germany and Egypt. This was expected based on the distance between the geographical regions from which the data (nucleotides sequences from 16S gene sequencing) for the phylogeny reconstruction were obtained. This is the first study to report Brucella species identified using 16S rRNA gene sequencing in East and Central Africa. A livestock vaccination program re-inforced with a high index of Brucella diagnosis is needed to eradicate brucellosis in animals and minimize suffering from Brucella infections in humans in Tanzania.

Factors Associated With Cryptosporidium Infection Among Adult HIV Positive Population in Contact With Livestock in Namwala District, Zambia.

Cryptosporidium spp. is one of the leading causes of diarrhoeal disease globally. In Zambia, the burden of Cryptosporidium infection in the general human population is unknown and factors associated with it are unclear. A study was conducted to determine the prevalence of Cryptosporidium spp. and identify factors associated with its infection among Human Immunodeficiency Virus (HIV) positive individuals in contact with livestock in Namwala district of Zambia. Three hundred and twenty six stool samples were collected from HIV infected individuals presenting at local health centers in Namwala district of Zambia between August 2015 and June 2016. The Meriflour Cryptosporidium/Giardia test kit was used to test for presence of oocysts. Demographic information such as age and sex and information on hypothesized risk factors was collected using a structured questionnaire. Overall prevalence of Cryptosporidium infection was 9.5% (95% CI = 6.7-13.2%); 13.3% and 7.1% among male and female participants, respectively. Males were 2.5 times more likely to be infected than females whereas the divorced had higher odds of being infected (OR = 14.8). Participants who kept animals had a higher prevalence (11.4%) than those that did not (7.0%). Those that shared water with neighbors were 5.7 times more likely to be infected than those who did not. We conclude that Cryptosporidium infection is prevalent among HIV positive adults in Namwala district and infection is associated with sex, marital status and sharing water sources among neighbors. Community sensitization is required to create awareness and reduce human exposure to Cryptosporidium infection.

Whole Genome Sequence Analysis Reveals Lower Diversity and Frequency of Acquired Antimicrobial Resistance (AMR) Genes in E. coli From Dairy Herds Compared With Human Isolates From the Same Region of Central Zambia.

Antibiotic treatment of sick dairy cattle is critical for the sustainability of this production system which is vital for food security and societal prosperity in many low and middle-income countries. Given the increasingly high levels of antibiotic resistance worldwide and the challenge this presents for the treatment of bacterial infections, the rational use of antibiotics in humans and animals has been emphatically recommended in the spirit of a "One Health" approach. The aim of this study was to characterize antimicrobial resistance (AMR) genes and their frequencies from whole genome sequences of Escherichia coli isolated from both dairy cattle and human patients in central Zambia. Whole genome sequences of E. coli isolates from dairy cattle (n = 224) and from patients at a local hospital (n = 73) were compared for the presence of acquired AMR genes. In addition we analyzed the publicly available genomes of 317 human E. coli isolates from over the wider African continent. Both acquired antibiotic resistance genes and phylogroups were identified from de novo assemblies and SNP based phylogenetic analyses were used to visualize the distribution of resistance genes in E. coli isolates from the two hosts. Greater acquired AMR gene diversity was detected in human compared to bovine E. coli isolates across multiple classes of antibiotics with particular resistance genes for extended-spectrum beta lactamases (ESBL), quinolones, macrolides and fosfomycin only detected in E. coli genomes of human origin. The striking difference was that the Zambian or wider African human isolates were significantly more likely to possess multiple acquired AMR genes compared to the Zambian dairy cattle isolates. The median number of resistance genes in the Zambian cattle cohort was 0 (0-1 interquartile range), while in the Zambian human and wider African cohorts the medians and interquartile ranges were 6 (4-9) and 6 (0-8), respectively. The lower frequency and reduced diversity of acquired AMR genes in the dairy cattle isolates is concordant with relatively limited antibiotic use that we have documented in this region, especially among smallholder farmers. The relatively distinct resistant profiles in the two host populations also indicates limited sharing of strains or genes.

Practices of traditional beef farmers in their production and marketing of cattle in Zambia.

Understanding the practices of traditional cattle farmers in developing countries is an important factor in the development of appropriate, pro-poor disease control policies, and in formulating regional-specific production incentives that can improve productivity. This paper describes the production, husbandry practices, economics, and constraints of traditional cattle farming in Zambia. A cross-sectional study design was used to obtain data from traditional cattle farmers (n = 699) using a structured questionnaire. Data analyses were carried out using SPSS and STATA statistical packages. The results revealed that the majority [65% (95% CI: 59.3-71.1)] of farmers practised a transhumant cattle herding system under communal grazing. In these transhumant herding systems, animal husbandry and management systems were found to be of poor quality, in terms of supplementary feeding, vaccination coverage, deworming, uptake of veterinary services, usage of artificial insemination, and dip tanks all being low or absent. East Coast Fever was the most common disease, affecting 60% (95% CI: 56.4-63.7) of farmers. Cattle sales were low, as farmers only sold a median of two cattle per household per year. Crop farming was found to be the main source of farm income (47%) in agro-pastoralist communities, followed by cattle farming (28%) and other sources (25%). The median cost of production in the surveyed provinces was reported at US$316, while that of revenue from cattle and cattle products sales was estimated at US$885 per herd per year. This translates to an estimated gross margin of US$569, representing 64.3% of revenue.There is considerable diversity in disease distribution, animal husbandry practices, economics, and challenges in traditional cattle production in different locations of Zambia. Therefore, to improve the productivity of the traditional cattle sub-sector, policy makers and stakeholders in the beef value chain must develop fit-for-purpose policies and interventions that consider these variations.

Identification and antimicrobial resistance patterns of bacterial enteropathogens from children aged 0-59 months at the University Teaching Hospital, Lusaka, Zambia: a prospective cross sectional study.

BACKGROUND: Bacterial diarrhoeal disease is among the most common causes of mortality and morbidity in children 0-59 months at the University Teaching Hospital in Lusaka, Zambia. However, most cases are treated empirically without the knowledge of aetiological agents or antimicrobial susceptibility patterns. The aim of this study was, therefore, to identify bacterial causes of diarrhoea and determine their antimicrobial susceptibility patterns in stool specimens obtained from the children at the hospital. METHODS: This hospital-based cross-sectional study involved children aged 0-59 months presenting with diarrhoea at paediatrics wards at the University Teaching Hospital in Lusaka, Zambia, from January to May 2016. Stool samples were cultured on standard media for enteropathogenic bacteria, and identified further by biochemical tests. Multiplex polymerase chain reaction was used for characterization of diarrhoeagenic Escherichia coli strains. Antimicrobial susceptibility testing was performed on antibiotics that are commonly prescribed at the hospital using the Kirby-Bauer disc diffusion method, which was performed using the Clinical Laboratory Standards International guidelines. RESULTS: Of the 271 stool samples analysed Vibrio cholerae 01 subtype and Ogawa serotype was the most commonly detected pathogen (40.8%), followed by Salmonella species (25.5%), diarrhoeagenic Escherichia coli (18%), Shigella species (14.4%) and Campylobacter species (3.5%). The majority of the bacterial pathogens were resistant to two or more drugs tested, with ampicillin and co-trimoxazole being the most ineffective drugs. All diarrhoeagenic Escherichia coli isolates were extended spectrum ß-lactamase producers. CONCLUSION: Five different groups of bacterial pathogens were isolated from the stool specimens, and the majority of these organisms were multidrug resistant. These data calls for urgent revision of the current empiric treatment of diarrhoea in children using ampicillin and co-trimoxazole, and emphasizes the need for continuous antimicrobial surveillance as well as the implementation of prevention programmes for childhood diarrhoea.

Phylogenomic approaches to determine the zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) isolated from Zambian dairy cattle.

This study assessed the prevalence and zoonotic potential of Shiga toxin-producing Escherichia coli (STEC) sampled from 104 dairy units in the central region of Zambia and compared these with isolates from patients presenting with diarrhoea in the same region. A subset of 297 E. coli strains were sequenced allowing in silico analyses of phylo- and sero-groups. The majority of the bovine strains clustered in the B1 'commensal' phylogroup (67%) and included a diverse array of serogroups. 11% (41/371) of the isolates from Zambian dairy cattle contained Shiga toxin genes (stx) while none (0/73) of the human isolates were positive. While the toxicity of a subset of these isolates was demonstrated, none of the randomly selected STEC belonged to key serogroups associated with human disease and none encoded a type 3 secretion system synonymous with typical enterohaemorrhagic strains. Positive selection for E. coli O157:H7 across the farms identified only one positive isolate again indicating this serotype is rare in these animals. In summary, while Stx-encoding E. coli strains are common in this dairy population, the majority of these strains are unlikely to cause disease in humans. However, the threat remains of the emergence of strains virulent to humans from this reservoir.

Prevalence of Giardia in dairy cattle in Lusaka and Chilanga districts, Zambia.

Giardia is an intestinal protozoan parasite of mammals including humans. A cross-sectional study was conducted to estimate prevalence of Giardia infections in smallholder and commercial dairy herds in Chilanga and Lusaka districts of Zambia. A total of 377 calves aged from 1 to 365 days were sampled on 34 farms. All faecal samples were analyzed for Giardia antigen using a commercially available ELISA kit. Overall prevalence of Giardia was 34.5% (95% CI=29.7-39.3). Among smallholder farms, animal level prevalence ranged from 0 to 100% (mean=44.6±36.9 standard deviations) and 12.5 to 60.9% (mean=33.5±16.7 standard deviations) within commercial herds. Prevalence was highest in calves less than three months old (p=0.010), and there was no significant difference in the prevalence between smallholder and commercial farms (p=0.300). Giardia prevalence was not associated with occurrence of diarrhoea in the calves (p=0.205). The study demonstrates that Giardia infections are common in dairy herds in the study areas, especially in calves less than three months of age.

Prevalence and patterns of antimicrobial resistance among Escherichia coli isolated from Zambian dairy cattle across different production systems.

This study focused on the use of antibiotics on small, medium and commercial-sized dairy farms in the central region of Zambia and its relationship to antibiotic resistance in Escherichia coli. A stratified random sample of 104 farms was studied, representing approximately 20% of all dairy farms in the region. On each farm, faecal samples were collected from a random sample of animals and a standardised questionnaire on the usage of antibiotics was completed. An E. coli isolate was obtained from 98.67% (371/376) of the sampled animals and tested for resistance to six classes of antibiotics. The estimated prevalence of resistance across the different farming systems was: tetracycline (10.61; 95%CI: 7.40-13.82), ampicillin (6.02; 95%CI: 3.31-8.73), sulfamethoxazole/ trimethoprim (4.49; 95%CI: 2.42-6.56), cefpodoxime (1.91; 95%CI: 0.46-3.36), gentamicin (0.89; 95%CI: 0.06-1.84) and ciprofloxacin (0%). Univariate analyses indicated certain diseases, exotic breeds, location, farm size and certain management practices as risk factors for detection of resistance, whereas multivariate analyses showed an association with lumpy skin disease and a protective effect for older animals (>25 months). This study has provided novel insights into the drivers of antibiotic use and their association with antibiotic resistance in an under-studied region of Southern Africa.

Study and ranking of determinants of Taenia solium infections by classification tree models.

Taenia solium taeniasis/cysticercosis is an important public health problem occurring mainly in developing countries. This work aimed to study the determinants of human T. solium infections in the Eastern province of Zambia and rank them in order of importance. A household (HH)-level questionnaire was administered to 680 HHs from 53 villages in two rural districts and the taeniasis and cysticercosis status determined. A classification tree model (CART) was used to define the relative importance and interactions between different predictor variables in their effect on taeniasis and cysticercosis. The Katete study area had a significantly higher taeniasis and cysticercosis prevalence than the Petauke area. The CART analysis for Katete showed that the most important determinant for cysticercosis infections was the number of HH inhabitants (6 to 10) and for taeniasis was the number of HH inhabitants > 6. The most important determinant in Petauke for cysticercosis was the age of head of household > 32 years and for taeniasis it was age < 55 years. The CART analysis showed that the most important determinant for both taeniasis and cysticercosis infections was the number of HH inhabitants (6 to 10) in Katete district and age in Petauke. The results suggest that control measures should target HHs with a high number of inhabitants and older individuals.

The contribution of veterinary medicine to public health and poverty reduction in developing countries.

Few studies have explicitly examined the linkages between human health, animal disease control and poverty alleviation. This paper reviews the contribution that veterinary medicine can make to poverty alleviation in sub-Saharan Africa. Our analysis attempts to explore aspects of this contribution under five themes: food production; food safety; impact and control of zoonotic infections; promotion of ecotourism; and environmental protection. While these areas of human activity have, more or less, fallen under the influence of the veterinary profession to varying degrees, we attempt to unify this mandate using a 'One Health' narrative, for the purpose of providing clarity on the linkages between the veterinary and other professions, livestock production and poverty alleviation. Future opportunities for improving health and reducing poverty in the context of developing African countries are also discussed. We conclude that veterinary science is uniquely positioned to play a key role in both poverty reduction and the promotion of health, a role that can be enhanced through the reorientation of the profession's goals and the creation of synergies with allied and related professions.

Foot and mouth disease in Zambia: spatial and temporal distributions of outbreaks, assessment of clusters and implications for control.

Zambia has been experiencing low livestock productivity as well as trade restrictions owing to the occurrence of foot and mouth disease (FMD), but little is known about the epidemiology of the disease in these endemic settings. The fundamental questions relate to the spatio-temporal distribution of FMD cases and what determines their occurrence. A retrospective review of FMD cases in Zambia from 1981 to 2012 was conducted using geographical information systems and the SaTScan software package. Information was collected from peer-reviewed journal articles, conference proceedings, laboratory reports, unpublished scientific reports and grey literature. A space-time permutation probability model using a varying time window of one year was used to scan for areas with high infection rates. The spatial scan statistic detected a significant purely spatial cluster around the Mbala-Isoka area between 2009 and 2012, with secondary clusters in Sesheke-Kazungula in 2007 and 2008, the Kafue flats in 2004 and 2005 and Livingstone in 2012. This study provides evidence of the existence of statistically significant FMD clusters and an increase in occurrence in Zambia between 2004 and 2012. The identified clusters agree with areas known to be at high risk of FMD. The FMD virus transmission dynamics and the heterogeneous variability in risk within these locations may need further investigation.

The incidence of human cysticercosis in a rural community of Eastern Zambia.

A community-based longitudinal study was performed in the Eastern Province of Zambia, in which repeated serological samplings were done to determine the incidence of human cysticercosis. Three sampling rounds were carried out at six months intervals. A total of 867 participants presented for all three samplings. All samples were tested for the presence of cysticercus antigens using a monoclonal antibody-based enzyme-linked immunosorbent assay (sero-Ag-ELISA), while a randomly selected sub-sample of 161 samples from each sampling round was tested for specific antibodies using a commercial enzyme-linked immunoelectrotransfer blot (EITB) assay. Stool samples (n = 226) were also collected during the final round of sampling for taeniosis diagnosis by coprology and coproantigen ELISA. Cysticercosis seroprevalence varied from 12.2% to 14.5% (sero-Ag) and from 33.5% to 38.5% (sero-Ab) during the study period. A taeniosis prevalence of 11.9% was determined. Incidence rates of 6300 (sero-Ag, per 100000 persons-year) and 23600 (sero-Ab, per 100000 persons-year) were determined. Seroreversion rates of 44% for sero-Ag and 38.7% for sero-Ab were recorded over the whole period. In conclusion, this study has shown the dynamic nature of T. solium infections; many of the people at risk become (re)infected due to the high environmental contamination, with a high number turning seronegative within a year after infection. An important number of infections probably never fully establish, leading to transient antibody responses and short-term antigen presence.

Bayesian modelling to estimate the test characteristics of coprology, coproantigen ELISA and a novel real-time PCR for the diagnosis of taeniasis.

OBJECTIVE: To estimate and compare the performances of coprology, copro-Ag ELISA and real-time polymerase chain reaction assay (copro-PCR) for detection of Taenia solium tapeworm carriers. METHODS: The three diagnostic tests were applied on 817 stool samples collected in two Zambian communities where taeniasis is endemic. A Bayesian approach was used to allow estimation of the test characteristics. Two (0.2%; 95% Confidence Interval (CI): 0-0.8), 67 (8.2%; 95% CI: 6.4-10.3) and 10 (1.2%; 95% CI: 0.5-2.2) samples were positive using coprology, copro-Ag ELISA and copro-PCR, respectively. RESULTS: Specificities of 99.9%, 92.0% and 99.0% were determined for coprology, copro-Ag ELISA and copro-PCR, respectively. Sensitivities of 52.5%, 84.5% and 82.7% were determined for coprology, copro-Ag ELISA and copro-PCR, respectively. CONCLUSIONS: We urge for additional studies exploring possible cross-reactions of the copro-Ag ELISA and for the use of more sensitive tests, such as copro-PCR, for the detection of tapeworm carriers, which is a key factor in controlling the parasite in endemic areas.

Challenges of controlling contagious bovine pleuropneumonia in sub-Saharan Africa: a Zambian perspective.

Contagious bovine pleuropneumonia (CBPP) is a disease of economic importance that is widely distributed in sub-Saharan African and contributes significantly to cattle morbidity and mortality. Control of CBPP offers a number of challenges as a result many developing countries in Africa are still struggling with this disease. In this study, we look at the challenges encountered in CBPP control in sub-Saharan Africa from the Zambian perspective. In conducting this study, we reviewed scientific literature and reports from the Ministry of Agriculture and Livestock and related animal institutions, and also made interviews with experts and key government officials involved in CBPP control in Zambia. Among the challenges identified for the successful control of CBPP were as follows: failure in the delivery of veterinary services, lack of a cattle identification system, natural phenomenon, livestock husbandry systems in the traditional sector, human movements, traditional practices among cattle farmers and cattle marketing systems. It was seen that the epidemiology of CBPP in Zambia is influenced by both ecological and anthological factors. Therefore, design and implementation of any control or eradication programme should be area/regional-dependent taking into account the different factors influencing disease transmission and maintenance.