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This study aimed to estimate the prevalence of poultry aspergillosis and evaluate the accuracy of histopathology (test under evaluation) and mycological culture (an imperfect reference test). Farms raising layer and breeder or broiler birds, with suspected aspergillosis cases, clinical or subclinical, were eligible and visited for sampling. After necropsy, histopathology and mycological culture examinations were conducted by two evaluators. A Bayesian latent class model was used to estimate the accuracy of histopathology when compared to the imperfect reference test, mycological culture. A total of 142 chicken farms, 96 laying and breeding hen farms, and 46 broiler farms were used for the study. True aspergillosis median prevalence was estimated at 63.7% (95% credibility intervals, CrI: 53.8%, 73.0%) in layers and breeders and at 65.2% (95% CrI: 50.2%, 78.3%) in the broiler farms' population. The median diagnostic sensitivity of histopathology and culture were estimated at, respectively, 98.8% (95% CrI: 94.6%, 100.0%) and 90.4% (95% CrI: 83.6%, 95.3%). Tests' diagnostic specificity was estimated at, respectively, 97.3% (95% CrI: 87.7%, 99.9%) and 95.7% (95% CrI: 91.8%, 98.2%). Both tests had very high and comparable positive predictive values, but, in a population where disease prevalence was 25%, histopathology had a higher negative predictive value than culture., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.)

Echinococcosis disease shows clinical signs similar to many diseases. Hence we report cases that need to be confirmed using appropriate tests. A confirmatory study has been conducted to assess the accuracy of two cytopathological tests, with the histopathology test as the reference standard. The first cytopathological test evaluates the Ziehl Neelsen staining with an epifluorescence microscope (cytopath 1). The second cytopathological test uses the same staining followed by a transmitted light microscope examination (cytopath 2). Of a total of 2524 inspected pigs, 101 suspected cases of echinococcosis were detected, of which 67 were found positive with the two cytopathological tests and the histopathological one. The specificity of cytopath 1 (100 % [95 % CI 100 - 100]) and cytopath 2 (100 % [95 % CI 100;100]) were similar, as well as their respective positive predictive values: 100 % [95 % CI 100 - 100] vs. 100 % [95 % CI 100 - 100]. The sensitivity of cytopath 1 is 79.66 % [95 % CI 69.39 - 89.93], while cytopath 2 equals 66.10 % [95 % CI 54.02 - 78.18]. The difference in sensitivity of both tests was not significant. Negative predictive values found for cytopath 1, and cytopath 2 were 40 [95 % CI 18.53 - 61.47] and 28.57 [95 % CI 11.84 - 45.3], leading to the Generalized Estimating Equations (GEE) Model estimate for an odds ratio of 1.4 [95 % CI 0.41 - 5.2], p = 0.06. Cytopath 1 and cytopath 2 are equivalent in terms of specificity (100 % [95 % CI 100 - 100] vs. 100 % [95 % CI 100;100]) and positive predictive value (100 % [95 % CI 100 - 100]. Cytopath 1 is more sensitive than cytopath 2 but not significant (79.66 % [ 95 % CI 69.39 - 89.93] vs. 66.10 % [95 % CI 54.02 - 78.18]). However, the negative predictive value of cytopath 1 is better than that of cytopath 2: 40 % [95 % CI 18.53 - 61.47] vs. 28.57 % [95 % CI 11.84 - 45.3]., Competing Interests: Conflict of Interest None declared., (© 2023 A. Toure et al., published by Sciendo.)

The epidemiology of corresponding tick-borne diseases has changed as a result of the recent introduction of Rhipicephalus (Boophilus) microplus to West Africa. The current study aimed to assess the diagnostic performance of an indirect ELISA for the detection of Babesia bovis infection in cattle. In a cross-section study, using a Bayesian Latent Class Model and iELISA diagnostic test for cattle babesiosis due to Babesia bovis, accuracy has been assessed with RT-PCR as an imperfect reference test. A total of 766 cattle were tested. The optimal diagnostic performances were obtained with 5% percentage of positivity. Sensitivity and specificity were, respectively, 0.94 [Cr. I.: 0.85−0.99] and 0.89 [Cr. I.: 0.87−0.92]. Additional diagnostic characteristics revealed that the Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were 96.6% [Cr. I.: 92.7−100%] and 82.2% [Cr. I.: 72−93%]. Overall, this test well discriminates an infected status from an uninfected status considering the area under the ROC curve (AUC) which was 0.78 [Cr. I: 0.72−0.85] and a Diagnostic Odds Ratio (DOR) of 127.8 [Cr. I.: 10.43−1562.27]. The AUC was significantly higher than 0.5 (p < 10−5). In consequence, this serologic assay could be suitable in moderate to high prevalence assessments.

Background: In cattle, genome-wide association studies (GWAS) have largely focused on European or Asian breeds, using genotyping arrays that were primarily designed for European cattle. Because there is growing interest in performing GWAS in African breeds, we have assessed the performance of 23 commercial bovine genotyping arrays for capturing the diversity across African breeds and performing imputation. We used 409 whole-genome sequences (WGS) spanning global cattle breeds, and a real cohort of 2481 individuals (including African breeds) that were genotyped with the Illumina high-density (HD) array and the GeneSeek bovine 50 k array., Results: We found that commercially available arrays were not effective in capturing variants that segregate among African indicine animals. Only 6% of these variants in high linkage disequilibrium (LD) (r 2  > 0.8) were on the best performing arrays, which contrasts with the 17% and 25% in African and European taurine cattle, respectively. However, imputation from available HD arrays can successfully capture most variants (accuracies up to 0.93), mainly when using a global, not continent-specific, reference panel, which partially reflects the unusually high levels of admixture on the continent. When considering functional variants, the GGPF250 array performed best for tagging WGS variants and imputation. Finally, we show that imputation from low-density arrays can perform almost as well as HD arrays, if a two-stage imputation approach is adopted, i.e. first imputing to HD and then to WGS, which can potentially reduce the costs of GWAS., Conclusions: Our results show that the choice of an array should be based on a balance between the objective of the study and the breed/population considered, with the HD and BOS1 arrays being the best choice for both taurine and indicine breeds when performing GWAS, and the GGPF250 being preferable for fine-mapping studies. Moreover, our results suggest that there is no advantage to using the indicus-specific arrays for indicus breeds, regardless of the objective. Finally, we show that using a reference panel that better represents global bovine diversity improves imputation accuracy, particularly for non-European taurine populations., (© 2022. The Author(s).)

Foot-and-mouth disease (FMD) affects the livestock industry and socioeconomic sustainability of many African countries. The success of FMD control programs in Africa depends largely on understanding the dynamics of FMD virus (FMDV) spread. In light of the recent outbreaks of FMD that affected the North-Western African countries in 2018 and 2019, we investigated the evolutionary phylodynamics of the causative serotype O viral strains all belonging to the East-Africa 3 topotype (O/EA-3). We analyzed a total of 489 sequences encoding the FMDV VP1 genome region generated from samples collected from 25 African and Western Asian countries between 1974 and 2019. Using Bayesian evolutionary models on genomic and epidemiological data, we inferred the routes of introduction and migration of the FMDV O/EA-3 topotype at the inter-regional scale. We inferred a mean substitution rate of 6.64 × 10 -3  nt/site/year and we predicted that the most recent common ancestor for our panel of samples circulated between February 1967 and November 1973 in Yemen, likely reflecting the epidemiological situation in under sampled cattle-exporting East African countries. Our study also reinforces the role previously described of Sudan and South Sudan as a frequent source of FMDVs spread. In particular, we identified two transboundary routes of O/EA-3 diffusion: the first from Sudan to North-East Africa, and from the latter into Israel and Palestine AT; a second from Sudan to Nigeria, Cameroon, and from there to further into West and North-West Africa. This study highlights the necessity to reinforce surveillance at an inter-regional scale in Africa and Western Asia, in particular along the identified migration routes for the implementation of efficient control measures in the fight against FMD., (© 2022 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Context and Purpose: In a context of recent introduction of Rhipicephalus (Boophilus) microplus tick species in West Africa, the purpose of the authors is to estimate incidence density of cattle babesiosis either caused by Babesia bigemina or Babesia bovis, and cattle anaplasmosis. Incidence density represents how quickly a disease or a condition is occurring amongst a group of individuals at risk., Methods: The longitudinal and prospective study design took place in south, centre, east, west and north of Côte d'Ivoire. Cattle have been followed for 12 months. At the end of each month, each animal has been RT-PCR tested for new infection by Babesia bovis, Babesia bigemina, and PCR-RFLP tested for new infection by Anaplasma marginale., Results: Findings show for the study area that incidence densities of Babesia bovis, Babesia bigemina and Anaplasma marginale infections in Côte d'Ivoire are, respectively, 15.3 new infections [95% CI 13.1-17.88] per 100 cattle, 32.2 new infections [95% CI 28.5-36.3] per 100 cattle, and 25.9 new infections [95% CI 22.5-29.6] per 100 cattle., Conclusion: Finally, there is increasing of infection incidence density following the region distance from the coast or elevation., (© 2022. The Author(s).)

Brucellosis is regarded as one of the highest burden zoonotic diseases to persist in many regions globally. While sustained vaccination against B. abortus in an endemic setting can markedly reduce the prevalence of large ruminant and human brucellosis and benefit local livelihoods, the implementation of effective and sustainable control programmes has often failed in the worst affected areas. In a cross-sectional study of 728 peri-urban dairy farmers in nine areas of six West and Central African countries, levels of commercialization and farm characteristics were examined alongside B. abortus seroprevalence estimates to hypothesize the most appropriate model for brucellosis vaccination delivery in each country. Demographic and economic data were collated and used to describe the farming systems currently in place. Furthermore, these data were utilized in a likelihood assessment to generate a quantitative score to hypothesize which of three private-public partnership (PPP) vaccine delivery models, that is 1) transformative, 2) transactional or 3) collaborative, would be most appropriate in each setting. The study sites had substantial differences in their levels of dairy commercialization and the farming practices employed; the heterogeneity across the study sites was evident in the conclusions of which models would be appropriate for vaccination delivery. While Lomé (Togo) had a strong indication for a transformative PPP model, Burkina Faso had strong indication for the collaborative PPP model. Of the remaining study sites, the scores were less dominant for any one model with Cameroon and Ivory Coast sites only just scoring highest on the transformative model and Senegal and Mali sites only just scoring highest on the collaborative model. Interestingly, none of the countries included in the study scored highest on the transactional model which currently is the most commonplace delivery model in the majority of sub-Saharan African countries., (© 2021 The Authors. Transboundary and Emerging Diseases published by Wiley-VCH GmbH.)

Functional rabies surveillance systems are crucial to provide reliable data and increase the political commitment necessary for disease control. To date, animals suspected as rabies-positive must be submitted to a postmortem confirmation using classical or molecular laboratory methods. However, most endemic areas are in low- and middle-income countries where animal rabies diagnosis is restricted to central veterinary laboratories. Poor availability of surveillance infrastructure leads to serious disease underreporting from remote areas. Several diagnostic protocols requiring low technical expertise have been recently developed, providing opportunity to establish rabies diagnosis in decentralized laboratories. We present here a complete protocol for field postmortem diagnosis of animal rabies using a rapid immunochromatographic diagnostic test (RIDT), from brain biopsy sampling to the final interpretation. We complete the protocol by describing a further use of the device for molecular analysis and viral genotyping. RIDT easily detects rabies virus and other lyssaviruses in brain samples. The principle of such tests is simple: brain material is applied on a test strip where gold conjugated antibodies bind specifically to rabies antigens. The antigen-antibody complexes bind further to fixed antibodies on the test line, resulting in a clearly visible purple line. The virus is inactivated in the test strip, but viral RNA can be subsequently extracted. This allows the test strip, rather than the infectious brain sample, to be safely and easily sent to an equipped laboratory for confirmation and molecular typing. Based on a modification of the manufacturer's protocol, we found increased test sensitivity, reaching 98% compared to the gold standard reference method, the direct immunofluorescence antibody test. The advantages of the test are numerous: rapid, easy-to-use, low cost and no requirement for laboratory infrastructure, such as microscopy or cold-chain compliance. RIDTs represent a useful alternative for areas where reference diagnostic methods are not available.

Aims: The aim of this work was to identify a protein which can be used for specific detection of antibodies against Bacillus cereus biovar anthracis (Bcbva), an anthrax-causing pathogen that so far has been described in African rainforest areas., Methods and Results: Culture supernatants of Bcbva and classic Bacillus anthracis (Ba) were analysed by gel electrophoresis, and a 35-kDa protein secreted only by Bcbva and not Ba was detected. The protein was identified as pXO2-60 by mass spectrometry. Sequence analysis showed that Ba is unable to secrete this protein due to a premature stop codon in the sequence for the signal peptide. Immunization of five outbred mice with sterile bacterial culture supernatants of Bcbva revealed an immune response in ELISA against pXO2-60 (three mice positive, one borderline) and the protective antigen (PA; four mice). When supernatants of classic Ba were injected into mice or human sera from anthrax patients were analysed, only antibodies against PA were detected., Conclusions: In combination with PA, the pXO2-60 protein can be used for the detection of antibodies specific against Bcbva and discriminating from Ba., Significance and Impact of the Study: After further validation, serological assays based on pXO2-60 can be used to perform seroprevalence studies to determine the epidemiology of B. cereus bv anthracis in affected countries and assess its impact on the human population., (© 2018 The Society for Applied Microbiology.)

Melioidosis is an often fatal infectious disease with a protean clinical spectrum, caused by the environmental bacterial pathogen Burkholderia pseudomallei . Although the disease has been reported from some African countries in the past, the present epidemiology of melioidosis in Africa is almost entirely unknown. Therefore, the common view that melioidosis is rare in Africa is not evidence-based. A recent study concludes that large parts of Africa are environmentally suitable for B. pseudomallei . Twenty-four African countries and three countries in the Middle East were predicted to be endemic, but no cases of melioidosis have been reported yet. In this study, we summarize the present fragmentary knowledge on human and animal melioidosis and environmental B. pseudomallei in Africa and the Middle East. We propose that systematic serological studies in man and animals together with environmental investigations on potential B. pseudomallei habitats are needed to identify risk areas for melioidosis. This information can subsequently be used to target raising clinical awareness and the implementation of simple laboratory algorithms for the isolation of B. pseudomallei from clinical specimens. B. pseudomallei was most likely transferred from Asia to the Americas via Africa, which is shown by phylogenetic analyses. More data on the virulence and genomic characteristics of African B. pseudomallei isolates will contribute to a better understanding of the global evolution of the pathogen and will also help to assess potential differences in disease prevalence and outcome.

Through full genome analyses of four atypical Bacillus cereus isolates, designated B. cereus biovar anthracis, we describe a distinct clade within the B. cereus group that presents with anthrax-like disease, carrying virulence plasmids similar to those of classic Bacillus anthracis. We have isolated members of this clade from different mammals (wild chimpanzees, gorillas, an elephant and goats) in West and Central Africa (Côte d'Ivoire, Cameroon, Central African Republic and Democratic Republic of Congo). The isolates shared several phenotypic features of both B. anthracis and B. cereus, but differed amongst each other in motility and their resistance or sensitivity to penicillin. They all possessed the same mutation in the regulator gene plcR, different from the one found in B. anthracis, and in addition, carry genes which enable them to produce a second capsule composed of hyaluronic acid. Our findings show the existence of a discrete clade of the B. cereus group capable of causing anthrax-like disease, found in areas of high biodiversity, which are possibly also the origin of the worldwide distributed B. anthracis. Establishing the impact of these pathogenic bacteria on threatened wildlife species will require systematic investigation. Furthermore, the consumption of wildlife found dead by the local population and presence in a domestic animal reveal potential sources of exposure to humans., Competing Interests: The authors have declared that no competing interests exist.