Review of epidemiological risk models for foot-and-mouth disease: Implications for prevention strategies with a focus on Africa.

Foot-and-mouth disease (FMD) is a highly infectious transboundary disease that affects domestic and wild cloven-hoofed animal species. The aim of this review was to identify and critically assess some modelling techniques for FMD that are well supported by scientific evidence from the literature with a focus on their use in African countries where the disease remains enzootic. In particular, this study attempted to provide a synopsis of the relative strengths and weaknesses of these models and their relevance to FMD prevention policies. A literature search was conducted to identify quantitative and qualitative risk assessments for FMD, including studies that describe FMD risk factor modelling and spatiotemporal analysis. A description of retrieved papers and a critical assessment of the modelling methods, main findings and their limitations were performed. Different types of models have been used depending on the purpose of the study and the nature of available data. The most frequently identified factors associated with the risk of FMD occurrence were the movement (especially uncontrolled animal movement) and the mixing of animals around water and grazing points. Based on the qualitative and quantitative risk assessment studies, the critical pathway analysis showed that the overall risk of FMDV entering a given country is low. However, in some cases, this risk can be elevated, especially when illegal importation of meat and the movement of terrestrial livestock are involved. Depending on the approach used, these studies highlight shortcomings associated with the application of models and the lack of reliable data from endemic settings. Therefore, the development and application of specific models for use in FMD endemic countries including Africa is encouraged.

Cross-sectional survey of brucellosis and associated risk factors in the livestock-wildlife interface area of Nechisar National Park, Ethiopia.

A cross-sectional survey was carried out to investigate the seroprevalence of ovine and bovine brucellosis in the livestock-wildlife interface area of Nechisar National Park, Ethiopia. Furthermore, producer's knowledge about brucellosis and its zoonotic potential was assessed using a structured questionnaire. A total of 268 cattle and 246 goat sera were collected from 50 herds and 46 flocks and subjected to Rose Bengal test (RBT) and enzyme-linked immunosorbent assay (ELISA) in parallel to detect anti-Brucella species antibodies. Positive reactions were further confirmed with compliment fixation test (CFT). Flock and herd level seroprevalence rate was 12.8% (95% CI 4.8-25.7) and 32.0% (95% CI 19.5-46.7) in goats and cattle, respectively. An overall animal-level seroprevalence of 4.5% (95% CI 2.25-7.86) and 9.7% (95% CI 6.44-13.89) was recorded for goats and cattle, respectively. Seroprevalence showed an increasing trend with age, where adult cattle > 2 years. Goats (> 1 year) recorded relatively higher seroprevalence, but the differences were not statistically significant. Similarly, female cattle and goats recorded a relatively higher seroprevalence, 11 and 5.6%, respectively, compared to males but the difference was not significant. However, a significant (P < 0.01) variation of seroprevalence was noted for parity (bovine), higher in animals in second parity, and abortion history, in both species, higher in animals that experienced abortion. Interviews revealed lack of awareness about brucellosis and food safety related to the zoonotic potential from consuming raw animal products (milk and meat). Ninety-eight percent of respondents did not consider handling abortion material is risky, and only a very low proportion (8%, n = 50) was able to mention limited zoonotic diseases (anthrax and Taenia cysticercosis) could be transmissible to people. The study indicated that brucellosis is endemic in domestic animals in the interface area and calls for further broad epidemiological investigation of the disease in livestock, human and wildlife following 'one health' unified research approaches beside enhancing public awareness.

Exploring the Diversity of Field Strains of Brucella abortus Biovar 3 Isolated in West Africa.

Brucellosis is one of the most widespread bacterial zoonotic diseases in the world, affecting both humans and domestic and wild animals. Identification and biotyping of field strains of Brucella are of key importance for a better knowledge of the epidemiology of brucellosis, for identifying appropriate antigens, for managing disease outbreaks and for setting up efficient preventive and control programmes. Such data are required both at national and regional level to assess potential threats for public health. Highly discriminative genotyping methods such as the multiple locus variable number of tandem repeats analysis (MLVA) allow the comparison and assessment of genetic relatedness between field strains of Brucella within the same geographical area. In this study, MLVA biotyping data retrieved from the literature using a systematic review were compared using a clustering analysis and the Hunter-Gaston diversity index (HGDI). Thus, the analysis of the 42 MLVA genotyping results found in the literature on West Africa [i.e., from Ivory Coast (1), Niger (1), Nigeria (34), The Gambia (3), and Togo (3)] did not allow a complete assessment of the actual diversity among field strains of Brucella. However, it provided some preliminary indications on the co-existence of 25 distinct genotypes of Brucella abortus biovar 3 in this region with 19 genotypes from Nigeria, three from Togo and one from Ivory Coast, The Gambia, and Niger. The strong and urgent need for more sustainable molecular data on prevailing strains of Brucella in this sub-region of Africa and also on all susceptible species including humans is therefore highlighted. This remains a necessary stage to allow a comprehensive understanding of the relatedness between field strains of Brucella and the epidemiology of brucellosis within West Africa countries.

Seroprevalence and potential risk factors for Brucella spp. infection in traditional cattle, sheep and goats reared in urban, periurban and rural areas of Niger.

INTRODUCTION: In Niamey, Niger, interactions within the interface between animals, humans and the environment induce a potential risk of brucellosis transmission between animals and from animals to humans. Currently, little is known about the transmission of Brucella in this context. RESULTS: 5,192 animals from 681 herds were included in the study. Serum samples and hygroma fluids were collected. A household survey enabled to identify the risk factors for transmission of brucellosis. The true adjusted herd-level prevalence of brucellosis ranged between 11.2% and 17.2% and the true adjusted animal-population level prevalence was 1.3% (95% CI: 0.9-1.8%) based on indirect ELISA test for Brucella antibodies. Animals aged of 1-4 years were found to be more susceptible than animals less than 1 year old (Odds ratio [OR] of 2.7; 95% CI: 1.43-5.28). For cattle, the odds of brucellosis seropositivity were higher in rural compared to the periurban areas (OR of 2.8; 95% CI: 1.48-5.17) whereas for small ruminants the risk of seropositivity appeared to be higher in urban compared to periurban areas (OR of 5.5; 95% CI: 1.48-20.38). At herd level, the risk of transmission was increased by transhumance (OR of 5.4; 95% CI: 2.84-10.41), the occurrence of abortions (OR of 3.0; 95% CI: 1.40-6.41), and for herds having more than 50 animals (OR of 11.0; 95% CI: 3.75-32.46). Brucella abortus biovar 3 was isolated from the hygromas. CONCLUSION: brucellosis in Niger is a serious problem among cattle especially in the rural areas around Niamey and among sheep in the urban areas of Niamey. The seroprevalence varies across strata and animal species with important risk factors including herd size, abortion and transhumance at herd level and age at animal population level. For effective control of brucellosis, an integrated approach seems appropriate involving all stakeholders working in public and animal health.

Importance of identification and typing of Brucellae from West African cattle: a review.

Bovine brucellosis is an endemic infectious disease which can impact cattle productivity and welfare negatively, as well as human health. Sufficient knowledge on its epidemiology, particularly on species and biotypes of Brucella at national and/or regional scale are important to set up and implement efficient control measures against brucellosis in a "One health" perspective. The main objective of this review was to investigate available literature on strains of Brucella in order to provide a state of art-knowledge on species and biovars reported in cattle from West Africa. A literature search was conducted to identify relevant data on species and biovars of Brucella in cattle from Western African countries. This search included studies presenting bacteriological and/or molecular results of identification and typing, relied on international classification methods with no time limit and no language restrictions. Studies reporting results of identification at genus level only were not considered for this review. This review revealed that Brucella abortus was the most prevalent species in cattle from West Africa, in line with host preference for Brucellae. So far, biovars 1, 2, 3, 4, 6 and intermediate biovar 3/6 of B. abortus were reported in cattle in the region. Among these strains, biovars 3, recently identified in The Gambia and Ivory Coast, was the most commonly isolated. Brucella melitensis and/or B. suis have not been mentioned yet in cattle in this part of Africa. The public health significance of prevailing strains is discussed and a regional collaborative control program of brucellosis is suggested.

Effect of a supplementation of Euphorbia heterophylla on nutritional meat quality of Guinea pig (Cavia porcellus L.).

The aim of the present work was to study the effect of dietary supplementation of Euphorbia heterophylla on the quality of the Guinea pig meat. Forty guinea pigs were divided into two groups fed ad libitum during 46 days a Panicum maximum diet (Panicum diet) or a mixed diet (75% Panicum maximum+25% Euphorbia heterophylla) (Paneuphorbia diet) to compare their effects on performances and on the composition of guinea pig tissues and carcass. Daily weight gain, liver weight, carcass yield, and the lipid content of both the carcass and the perirenal fat were significantly increased by the Paneuphorbia diet. Feeding Paneuphorbia diet increased (P<0.05) the n-3 PUFA content in perirenal fat, muscle, liver and in the carcass and decreased (P<0.05) the n-6/n-3 ratios in all these tissues and the carcass. In conclusion, this study shows that Euphorbia heterophylla is a source of n-3 fatty acids which can improve significantly the n-3 PUFA content of Guinea pig meat and carcass.

Bayesian estimation of the true prevalence, sensitivity and specificity of the Rose Bengal and indirect ELISA tests in the diagnosis of bovine brucellosis.

Serology is the most convenient method for detecting brucellosis but the efficient use of such tests in disease control requires evaluation of diagnostic performance and discriminative ability. The objective of this study was to assess the performance of the Rose Bengal test (RBT) and an indirect ELISA (iELISA) in diagnosing brucellosis in 995 serum samples collected from cattle in the Ivory Coast between 2005 and 2009. A Bayesian approach was used to evaluate the two tests by estimating their sensitivities and specificities. The correlation-adjusted sensitivity of the iELISA was estimated to be 96.1% (credibility interval [CrI], 92.7-99.8), whereas that of the RBT was 54.9% (CrI, 23.5-95.1). High correlation-adjusted specificities were found for both tests (95.0%; [CrI, 91.1-99.6] for the iELISA and 97.7%; [CrI, 95.3-99.4] for the RBT, respectively). The true prevalence of brucellosis was estimated from the serum samples to be 4.6% (95%; [CrI, 0.6-9.5]). The level of agreement between the two tests was evaluated using indices of agreement (n=995). Good agreement was found for negative results (96.6%; confidence interval [CI], 95.7-97.4), a finding supported by an estimated significant correlation of 0.37 (95%; CI, 0.01-0.73) within the sera testing negative. Agreement was lower for sera testing positive (52.2% CI: 41.9-62.5). The findings highlight the importance of using these two tests in combination as part of any brucellosis control programme.

Intersectoral collaboration between the medical and veterinary professions in low-resource societies: The role of research and training institutions.

BACKGROUND: Neglected zoonoses continue to significantly affect human health in low-resource countries. A symposium was organised in Antwerp, Belgium, on 5 November 2010 to evaluate how intersectoral collaboration among educational and research institutions could improve the situation. RESULTS: Brucellosis and echinococcosis were presented as models for intersectoral collaboration. Low-resource societies face evident knowledge gaps on disease distribution, transmission within and across species and impact on human and animal health, precluding the development of integrated control strategies. RECOMMENDATIONS: While veterinarians have been the main driver of the One Health initiative, the medical profession does not seem to be fully aware of how veterinary science can contribute to human public health. It was postulated that transdisciplinarity could help fill knowledge gaps and that encouraging such transdisciplinarity should start with undergraduate students. Furthermore, intersectoral collaboration on zoonoses should not ignore the social sciences (e.g. assessment of indigenous knowledge and perception; participatory surveillance), which can contribute to a better understanding of the transmission of diseases and improve communities' participation in disease control activities.

Risk factors associated with brucellosis seropositivity among cattle in the central savannah-forest area of Ivory Coast.

Serological results obtained from 907 serum samples collected from unvaccinated cattle of at least 6 months of age in the savannah-forest region of Ivory Coast were used to investigate risk factors associated with bovine brucellosis seropositivity. Serum samples were tested using the Rose Bengal test (RBT) and indirect enzyme linked immunosorbent assay (iELISA). Using a parallel interpretation, RBT and iELISA results showed that 10.3% (95% confidence interval (CI): 8.4, 12.4) of the cattle had antibodies against Brucella in our study area. The logistic regression analysis indicated that brucellosis seropositivity was associated with age and herd size. Cattle above 5 years of age were found to have a higher chance of being seropositive (odd ratio (OR)=2.8; 95% CI: 1.3, 6.4) compared to cattle under 3 years of age. Similarly, the odd of brucellosis seropositivity for herds with more than 100 cattle was 3.3 (95% CI: 1.2, 8.9) times higher compared to those with less than 50 cattle.

Treatment of depression in first episode of schizophrenia: results from EUFEST.

Depressive symptomatology is an important target of treatment in first episode schizophrenia. This reanalysis of the European First Episode Schizophrenia Trial (EUFEST) describes the depressive symptomatology and the effect of antipsychotic treatment in patients suffering from first episode schizophrenia and schizophreniform disorder randomized to treatment with low dose haloperidol (n=103), amisulpride (n=104), olanzapine (n=105), quetiapine (n=104) or ziprasidone (n=82) for one year. At baseline, the mean score on the Calgary Depression Scale for Schizophrenia (CDSS) was 5.1 (±4.9) with 38.3% of patients having a CDSS score≥6, i.e. clinically relevant depressive symptom severity. During treatment depression scores decreased, the mean CDSS score being 1.1 (±2.1) and 3.0% of patients having a CDSS≥6 at 52 weeks. The proportion of patients using antidepressants during the complete trial was 18.5% in the haloperidol group, 28.6% in the olanzapine group compared to 5.8% in the quetiapine group, 12.5% in the amisulpride group, and 9.8% in the ziprasidone group. There were no differences over time in the probability of being depressed (CDSS≥6) between the 5 treatment groups after adjustment for antidepressant use, nor in a sub analysis of patients who did not take any antidepressant. Depression scores at baseline or during the trial had no effect on treatment discontinuation or on the reduction of positive symptoms. In summary, the results of EUFEST did not demonstrate a differential effect of the antipsychotics studied on depressive symptomatology in patients with first episode schizophrenia.

Economic burden of bovine trypanosomosis in three villages of Metekel zone, northwest Ethiopia.

The study was carried out to assess the economic burden of trypanosomosis in three villages of the Metekel zone in 2009. The disease was found to cause substantial economic losses through cattle mortality, drug purchase, and draft power loss of infected oxen. The farmers in the area were spending a significantly (p < 0.05) higher amount of money for the treatment of trypanosomosis than all other diseases combined. The overall mortality rate of cattle due to trypanosomosis was 4.4%. The mortality was significantly higher (p < 0.05) in an area where trypanosomosis prevalence was also higher. Many of the farmers prioritized losses of draft power as the most important impact of the disease. The overall prevalence of the disease was 12.1%. The disease burden was significantly (p < 0.05) higher in the rainy season than at other times of the year. In general, farmers had good knowledge on the signs and seasonality of trypanosomosis. Thus, tsetse suppression activities that involve the local community can be an important tool towards minimizing the economic burden of the disease in the area.

Bovine tuberculosis prevalence survey on cattle in the rural livestock system of Torodi (Niger).

BACKGROUND: Bovine tuberculosis (BTB) is a widespread zoonosis in developing countries but has received little attention in sub-Saharan Africa, especially in Niger. Recent investigations confirmed the high incidence of the disease in cattle slaughtered in an abattoir in Niamey. The fact that most of the animals in which M. bovis has been identified were from the rural area of Torodi implied the existence of a probable source of BTB in this region. This study aimed to determine the prevalence of BTB infection in cattle and to identify risk factors for infection in human and cattle populations in Torodi. METHODS AND PRINCIPAL FINDINGS: A survey was carried out at the level of households keeping livestock (n = 51). The questionnaire was related to the potential risk factors and the presence of clinical signs of TB both in animals and humans. Comparative Intradermal Tuberculin Test was conducted to determine the TB status in cattle (n = 393). The overall apparent individual animal prevalence of tuberculin reactors was 3.6% (CI: 95%, 1.9-5.9), whereas the individual true prevalence was estimated at 0.8% (CI: 95%, 0.0-5.0). Using a multivariate logistic regression analysis and a classification tree analysis, the only household level risk factor that significantly influenced the presence of BTB in cattle was the presence of animals coughing in the herd (OR = 4.7, 95% CI: 1.12-19.71, p-value = 0.034). The lack of the practice of quarantine was borderline significant (OR = 4.2, 95% CI: 0.96-18.40, p-value = 0.056). CONCLUSION/SIGNIFICANCE: The study confirmed that BTB is endemic in cattle in Torodi and the risk of the transmission of the disease to humans is potentially high. For the control of the disease in livestock, slaughtering of infected animals and the compensation of the owners is needed. Collaboration between the veterinary and the medical sectors, in the diagnosis, monitoring, prevention and control of BTB is strongly encouraged.

Methodology for assessing determinants of manure use in urban areas of Africa.

The objectives of this study were to identify the major determinants (e.g. zootechnical and socio-economic parameters) of manure management practised by urban livestock keepers. Data were collected from four single-visit, multi-object surveys in three cities of Africa. The livestock keepers were classified either as 'good user' or 'bad user' of manure depending on how they use the manure. The results of this study indicate that the habit of manure utilization shows geographical differences. In general, livestock keepers engaged in agricultural activities are good manure users. Furthermore, manual workers, traders or the self-employed are better manure users than other professional groups. The manure utilization varies also in function of the livestock numbers. In Brazzaville, the habit of selling animals influenced manure management positively. Experience of keeping livestock before the civil war in Brazzaville was also a determining factor of manure use in the post-war urban livestock keeping in 2001. When designing policies to reduce the environmental effects of urban livestock keeping, the highlighted factors can assist city planners to understand how urban livestock keepers use manure. Using the non-parametric classification tree method CART, two approaches were used to select an optimal classification of 'bad' manure users: the 'Cook and Goldman rule' and the 'Classification with different misclassification cost ratios' method. The optimal tree was selected by using receiver operating characteristics curve information. This method can be useful in assessing other aspects of waste management.