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

Classification tree produced using CART with target variable “CITT” (1 having at least one animal tested positive by CITT within the household; 0: not having animals tested positive by CITT within the household).

<p>Classification tree representing the important factors influencing CITT positivity. Target variable is “CITT” (1 having at least one animal tested positive by CITT within the household; 0: not having animals tested positive by CITT within the household). The following variables were selected by the tree as important factors: herd size with a cut off of 19 cattle in the herd; Handling (quarantine: keeping newly arrived animals out of the herd – mixed: new animals mixed with the other animals); Animals chronic cough (0 = absence of animals with chronic cough in the herd and 1 = presence of animals with chronic cough).</p

Location of the study zone (Torodi) in Niger.

<p>Location of the study zone (Torodi) in Niger.</p

Results of the final multivariable logistic regression model using backward stepwise selection with significant household level risk factors for bovine tuberculosis in the Torodi zone of Niger.

<p>Ref: indicate that the level is taken as the reference to which others are compared;</p><p>*: quarantine was practiced;</p><p>**: mixed newly arrivals animals.</p

Apparent prevalence in local cattle (n = 393) in the rural zone of Torodi, Niger.

<p>Apparent prevalence (AP) and estimation of the true prevalence (TP) of bovine tuberculosis among local cattle (n = 393) in the rural zone of Torodi, Niger. TP was calculated using the value of Sensitivity and Specificity for the cut-off of >4 mm according to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0024629#pone.0024629-Alambedji1" target="_blank">[8]</a>.</p

Anonimiziranje sodb in obdelava osebnih podatkov

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

Univariate analysis of raw data indicating potential risk factors associated with bovine tuberculosis (BTB) in cattle and humans in the rural area of Torodi, Niger.

<p>*These values had <i>P</i>-value<0.25 and were identified as potential risk factors for inclusion in the multivariable analysis; Ref: indicate that the level is taken as the reference to which others are compared; ND: not determined;</p><p>**Target variable for multivariate analysis and CART analysis.</p

Within herd apparent prevalence in local cattle (n = 393) in the rural zone of Torodi, Niger.

<p>Apparent prevalence (AP) and estimation of the true prevalence (TP) of bovine tuberculosis among local cattle (n = 393) in the rural zone of Torodi, Niger. TP was calculated using the value of Sensitivity and Specificity for the cut-off of >4 mm according to Ameni et al. (2008).</p><p>*Number of households in which animals were tested by comparative intra-dermal tuberculin testing (CITT).</p

Ranking of BTB risk factors by overall discriminatory power using CART.

<p>Ranking of BTB risk factors by overall discriminatory power using CART.</p

Corrélations entre les caractéristiques phénotypiques et détermination d’une formule barymétrique chez le taurin Kouri du Niger

Objectif: Cette étude vise à contribuer à la connaissance des caractéristiques phénotypiques du taurin Kouri du Niger.Méthodologie et résultats: Les caractéristiques phénotypiques du taurin Kouri du Niger ont fait l’objet d’une étude conduite dans la région de Diffa au niveau des sites situés aux alentours de Kinjandi dans la commune de Gueskerou et au Centre Secondaire de Multiplication du Bétail de Sayam. Des mensurations ont été effectuées directement sur des animaux et ont permis d’enregistrer des paramètres quantitatifs. Des paramètres qualitatifs ont été renseignés sur la base de l’observation des animaux. Un total de 475 animaux (423 femelles, 36 mâles entiers et 16 mâles castrés) âgés d’au moins 4 ans a été concerné par l’étude. Les moyennes des paramètres phénotypiques quantitatifs suivants ont été notées : Hauteur au garrot (HG) : 125,65±6,08 cm ; Périmètre thoracique (PT) : 157,95±10 cm ; Hauteur au sacrum (HS) : 133,50±6,10 cm ; Largeur aux ischions (LI) : 14,41±2,75. Des différences significatives ont été observées entre les sexes. Le PT est le paramètre le plus corrélé au poids avec un coefficient de corrélation de 0,843. Trois modèles barymétriques sont proposés et ont permis de noter des coefficients d’ajustement de R12=0,79 ; R22= 0,74 et R32= 0,71. Les paramètres phénotypiques qualitatifs ont fait ressortir un profil rectiligne dominant (85,86%) ; des oreilles à orientation latérale (99,79 %) ; des cornes présentes (97,89%) et fixées (97,41%), un dos rectiligne chez 86,50% des animaux. Aussi la couleur blanche de la robe domine avec 50,84 %. Conclusion et application des résultats: En somme, le taurin Kouri du Niger peut être considéré comme une race assez hétérogène sur le plan phénotypique. Cette variabilité pourrait être favorable à une sélection en vue d’une amélioration génétique de la race.Mots clés: phénotype, formule barymétrique, taurin Kouri, NigerEnglish Title: Correlations between Phenotypic measurements and determination of a Barymetric Formula in Niger Kuri cattle breedEnglish AbstractObjective: The main objective of this study is to contribute to increase knowledge on Niger Kuri phenotypic characteristics.Methodology and Results: Phenotypic characteristics of Niger Kuri cattle breed have been assessed in the region of Diffa, Niger, including sampling sites around Kinjandi in Gueskerou commune, and in the Sayam Cattle Secondary Multiplication Center. Measurements were made directly on animals and allowed to record quantitative parameters. Qualitative parameters were given based on the observation of the animals. A total of 475 individuals (423 females, 36 males and 16 castrated males) with at least 4 years age have been sampled. The means values of phenotypic traits measured were as follow: quantitative phenotypic parameters were measured. Height at withers: 125.65 ± 6.08 cm, Heart girth: 157.95 ± 10 cm, height at hips: 133. 50 ± 6.10 cm, Ischium width: 14.41 ± 2.75. Significant differences were observed between sexes. Heart girth is the most correlated parameter to the weight with a correlation coefficient of 0.843. Three barymetric models were used and showed adjusted coefficients of R12 = 0.79, R22 = 0.74 and R32 = 0.71. The qualitative phenotypic parameters revealed à dominant straight profile (85.86%), lateral oriented ears (99.79%), presence of horns (97.89%) and fixed (97.41%), straight back (86.50%) among the individuals. Besides, the white color pattern is predominant (50.84 %).Conclusion and application of results: Overall, Niger Kuri cattle breed may be considered as heterogeneous breed at phenotypic level. This variability may be favorable for selection strategy for this valuable breed improvement.Keywords: phenotype, barymetric formula, Kuri, Nige