Tuberculosis in Goats and Sheep in Afar Pastoral Region of Ethiopia and Isolation of Mycobacterium tuberculosis from Goat

Identification of peste des petits ruminants virus along with co-infecting diseases of goats in Bangladesh

OBJECTIVE

Peste des petits ruminants (PPR) virus is the main infectious cause of goat mortality in Bangladesh, and co-infection may make diseases more severe. This study aimed to detect PPR and co-infecting diseases in goats.

MATERIALS AND METHODS

One hundred goats suspected to be infected with the PPR virus were collected from various areas of Mymensingh district, Bangladesh. A systemic post-mortem examination was carried out on PPR-suspected goats. Lungs, spleen, and lymph nodes (pre-scapular) were used for ribonucleic acid extraction, whereas lungs and mesenteric lymph nodes were used for deoxyribonucleic acid extraction. Seven-pair primer sets were used for molecular detection of pathogens specific for PPR, goat pox, contagious ecthyma (Orf), foot and mouth disease (FMD) virus, Klebsiella sp., and Mycobacterium sp. Reverse transcriptase-polymerase chain reaction (RT-PCR) or polymerase chain reaction (PCR) were used to find the exact cause.

RESULTS

Out of 100 PPR-suspected goats examined, 55 goats were confirmed as PPR-detected by RT-PCR. Among the 55 PPR-positive goats, 2 were co-infected with goat pox, 2 with tuberculosis, 10 with Klebsiella sp. infection, and 6 with FMD as detected by PCR and RT-PCR. Moreover, 12 goats were co-infected with PPRV and fascioliasis.

CONCLUSION

About 58% of PPR virus-infected goats were co-infected with other organisms. There is a need to design technology to detect the state of co-infectivity at its early onset and future preventive and therapeutic strategies for co-infecting diseases. This is the first study in Bangladesh to describe co-infecting diseases of goats along with PPR.

Review on Bovine Tuberculosis: An Emerging Disease Associated with Multidrug-Resistant Mycobacterium Species

Bovine tuberculosis is a serious infectious disease affecting a wide range of domesticated and wild animals, representing a worldwide economic and public health burden. The disease is caused by Mycobacteriumbovis and infrequently by other pathogenic mycobacteria. The problem of bovine tuberculosis is complicated when the infection is associated with multidrug and extensively drug resistant M. bovis. Many techniques are used for early diagnosis of bovine tuberculosis, either being antemortem or postmortem, each with its diagnostic merits as well as limitations. Antemortem techniques depend either on cellular or on humoral immune responses, while postmortem diagnosis depends on adequate visual inspection, palpation, and subsequent diagnostic procedures such as bacterial isolation, characteristic histopathology, and PCR to reach the final diagnosis. Recently, sequencing and bioinformatics tools have gained increasing importance for the diagnosis of bovine tuberculosis, including, but not limited to typing, detection of mutations, phylogenetic analysis, molecular epidemiology, and interactions occurring within the causative mycobacteria. Consequently, the current review includes consideration of bovine tuberculosis as a disease, conventional and recent diagnostic methods, and the emergence of MDR-Mycobacterium species.

Intradermal comparative cervical tuberculin test in the diagnosis of caprine tuberculosis

Tuberculosis remains one of the most important infectious diseases with well-known zoonotic nature that affect humans, wildlife, and domestic animals, including goats. Nonetheless, no intradermal tuberculin test has been standardized for caprine diagnosis of tuberculosis. The present study investigated the intradermal comparative cervical tuberculin test (ICCTT) in the diagnosis of tuberculosis among 60 goats from farms with history of tuberculosis. The cutoff applied to goats was based on a study where goats had been experimentally infected with Mycobacterium bovis and Mycobacterium avium. Clinical examination, bacteriological culture, and histopathological staining were assessed to the diagnosis. Isolates compatible with mycobacteria were subjected for molecular diagnosis based on gyrB-restriction fragment length polymorphism (RFLP) analysis and PCR restriction-enzyme analysis (PRA) of hsp65 gene by BstEII and HaeIII, namely PRA-hsp65 assay. From all goats, 60% (n = 36/60), 3.3% (n = 2/60), and 36.7% (n = 22/60) showed positive, inconclusive, and negative reactions, respectively. Out of 36 goats with ICCTT positive, 75% (n = 27/36) had isolation of mycobacteria and were detected M. bovis by gyrB-RFLP. Molecular diagnosis and histopathological findings compatible with tuberculosis showed 86.1% (n = 31/36) concordance with the ICCTT. When compared ICCTT with M. bovis isolation, gyrB-RFLP, and histopathology, the better arithmetic means of sensitivity and specificity were 2.5 mm for ICCTT compared with M. bovis isolation and gyrB-RFLP, and 4.55 mm when compared with histopathology. Both receiver operating characteristic (ROC) curves presented statistical significance (P < 0.001). The identification of other mycobacteria, e.g., M. kansasii, M. flavescens, M. avium, M. florentinum, M. lentiflavum, M. simiae, and Corynebacterium pseudotuberculosis, not influenced positive results in ICCTT. The concordance between bacteriological, histopathological, and molecular identification with ICCTT findings indicate that the tuberculin test may be used as a valuable tool for diagnosis of caprine tuberculosis and reinforce the importance of association of methods to diagnostic of the disease from animal origin.

Evaluation of Postmortem Inspection Procedures to Diagnose Bovine Tuberculosis at Debre Birhan Municipal Abattoir

Simple Summary

Tuberculosis is transmitted from animal to human by consuming raw or under cooked meat and milk from infected animals. Careful meat inspection considering all parts of the carcass is very important. However, most abattoirs in Ethiopia are performing only routine meat inspection which does not examine the organs in detail. Failure to do so might result in undetected lesions. In this study, two methods (routine and detailed meat inspections) were compared to inspect carcasses at abattoir level. Our study clearly shows that the routine meat inspection method misses about 89% of the tuberculosis lesions identified by detailed meat inspection. Based on detailed meat inspection, overall 4.7% of lesions suggestive of bovine tuberculosis (bTB) were found in the carcass of cattle slaughtered at Debre Birhan municipality abattoir during the study period. However, the routine meat inspection only detected 0.5% of the carcasses examined as having Tuberclosis (TB) lesions. Anatomically, 66% of the lesions were found in the lungs and associated lymph nodes, 21% in lymph nodes of the head, and 13% in the lymph nodes of the gastrointestinal tract. Therefore, lesion distribution routine and detailed meat inspection and their sensitivity with respect to lesion detection was identified.

Abstract

Routine meat inspection in the abattoir was used to examine carcass for subsequent approval for consumption. However, the chance of missing lesions results in approval of carcass and/or the offal with lesions of tuberculosis. A cross-sectional study was conducted at Debre Birhan Municipal abattoir from October 2016 to May 2017. Lesion prevalence estimation and two meat inspection procedures’ efficacy evaluation was attempted. The breeds of the animals inspected were zebu breeds. Routine abattoir meat inspection involves visual inspection, palpation and incision of intact organs such as the liver and kidneys, as well as inspection, palpation and incision of tracheobronchial, mediastinal and prescapular lymph nodes. The detailed meat inspection involves inspection of each of the carcass. In this case, the seven lobes of the two lungs, lymph nodes and organs were also thoroughly examined. The cut surfaces were examined under bright light sources for the presence of an abscess, cheesy mass, and tubercles in detail. The study involved and compared both routine and detailed meat inspections at the abattoir. Chi-square test of independence and odds ratio were used to see the association of lesion and different risk factors. Based on detailed meat inspection, the overall lesion prevalence of bovine tuberculosis in the carcass of cattle slaughtered at Debre Birhan municipality abattoir was found to be 4.7% but only 0.5% of the carcass examined had detectable bovine tuberculosis lesions when routine abattoir meat inspection alone was used. The majority of the lesions were distributed to the lungs and associated lymph nodes. There was a significant association (p < 0.05) in TB infection rate and body condition score. In conclusion, this study has clearly indicated the prevalence of bovine tuberculosis lesions in the abattoir that are missed by routine abattoir meat inspection. In addition, it showed low sensitivity of the routine meat inspection procedure used. Hence, our study warrants immediate attention to strengthen the current meat inspection practices at Debre Birhan public abattoir.

Specificity of serological test for detection of tuberculosis in cattle, goats, sheep and pigs under different epidemiological situations

BACKGROUND

Serum antibody detection has potential as a complementary diagnostic tool in animal tuberculosis (TB) control, particularly in multi-host systems. The objective of the present study was to assess the specificity (Sp) of an enzyme-linked immunosorbent assay (ELISA) based on the new multiprotein complex P22 for the detection of specific antibodies against the Mycobacterium tuberculosis complex (MTC) in the four most relevant domestic animals acting as MTC hosts: cattle, goat, sheep and pig. We used sera from an officially TB-free (OTF) country, Norway, and from a non-OTF one, Spain. The samples included sera from goats that had been vaccinated against M. avium subsp. paratuberculosis (MAP) and sheep from a herd in which Corynebacterium pseudotuberculosis had been isolated.

RESULTS

In cattle, the Sp ranged from 92.5 (IC95% 90.7-94) to 99.4% (IC95% 98.3-99.8) depending on the cut-off used and the origin of the samples (Spain or Norway). Sp in cattle (cut-off point 100) was significantly higher (P < 0.05) for Norwegian samples. By contrast, Sp in goats was consistently low at the 100 cut-off [30.9 (CI95%23.4-39.5)-78% (CI95% 68.9-85)]. A higher cut-off of 150 improved Sp in Norwegian goats [97% (CI95% 91.6-99)], but still yielded a poor Sp of 56.1% (CI95% 47.3-64.6) in Spanish goats. In Norway at the 100 cut-off the Sp was 58.3 (CI95% 42.2-72.9) and 90.6% (CI95% 81-95.6) in MAP vaccinated and non-vaccinated goats, respectively, indicating interference due to MAP vaccination. Sp in sheep was between 94.4 (CI95% 91.7-96.3) and 100% (CI95% 96.3-100) depending on the cut-off and country, and no diagnostic interference due to infection with C. pseudotuberculosis was recorded. Sp in pigs was 100%, regardless the cut-off point applied, and no significant differences were observed between pigs from Norway and from Spain.

CONCLUSIONS

Due to its excellent Sp in pigs and acceptable Sp in cattle and sheep, this ELISA may constitute a suitable option for TB screening at herd level, particularly in OTF-countries.

Prevalence of bovine tuberculosis in cattle, goats, and camels of traditional livestock raising communities in Eritrea

Background

The aim of the current study was to assess the prevalence of bovine tuberculosis (BTB) in cattle, goats, and camels, and its zoonotic potential within the traditional livestock raising communities in four regions of Eritrea. The Single Intradermal Comparative Tuberculin Test (SICTT) as indicator of M. bovis infection was conducted on 1077 cattle, 876 goats, and 195 camels. To elucidate possible risk factors for BTB transmission between animals and its potential zoonotic implication, questionnaire based face-to-face interviews were conducted in households of which 232 raised cattle, 128 goats, and 29 camels.

Results

The results of the SCITT were interpreted using the OIE standard (> 4 mm cut-off) for positive responses. In cattle, individual animal (n = 1077) and herd (n = 413) prevalences were 1.2% (n = 13) [Confidence Interval (CI) 95% CI, 1.0–1.3%] and 3.2% (n = 13) (95% CI, 3.0–3.4%), respectively. In goats (n = 876), none of the animals was positive. In camels, individual animal (n = 195) and herd (n = 70), BTB prevalences were 1.5% (n = 3) (95% CI,1.4–1.6%) and 2.9(n = 2) (95% CI, 0.9–4.6%), respectively. Overall, male animals were more at risk (OR = 2.6; 95% CI:1.0–8.7) when compared to females. Sharing of water points, introduction of new animals into herds and migration of animals over large distances were common events that may contribute to intra and inter-species transmission of BTB. Consumption of raw milk, lack of BTB transmission awareness, and low levels of education were common in the farming communities.

Conclusion

The current study highlighted a low prevalence of M. bovis in cattle, goats and camels in extensive traditional livestock in Eritrea. Despite this, the spatial distribution of affected animals across most of the sampled regions and consumption of unpasteurized milk warrants surveillance, cautious and timely control measures for the disease.

Electronic supplementary material

The online version of this article (10.1186/s12917-018-1397-0) contains supplementary material, which is available to authorized users.

Preliminary investigation of the transmission of tuberculosis between farmers and their cattle in smallholder farms in northwestern Ethiopia: a cross-sectional study

Background

The feeding habits and close physical contact between Ethiopian farmers and their cattle promote the transmission of tuberculosis (TB) between the farmers and their cattle. This study aimed to investigate the transmission of TB between farmers and their cattle in smallholder farms in northwestern Ethiopia.

Results

A total of 70 human TB lymphadenitis (TBLN) cases visiting the Felegehiwot Comprehensive Specialized Hospital in Bahir Dar City and 660 cattle were investigated. Half of the cattle were owned by households with TB cases, and the remaining half by TB free households. Among the 70 human TBLN patients interviewed, 65.7% (46 out of 70) of the respondents were not aware of zoonotic TB, and 67.1% (47/70) of them consumed raw milk. Positive cultures of TB were obtained in 40 of the 70 cases where TBLN tests were positive with fine needle aspiration cytology. Spoligotyping resulted in 31 different patterns, of which 25 isolates were Mycobacterium (M.) tuberculosis, and the remaining were M. africanum (4 isolates) and M. bovis (2 isolates). None of the animals showed positive test results for bovine TB by comparative intradermal tuberculin test.

Conclusions

Based on the identification of M. bovis from two patients diagnosed with TBLN, we obtained preliminary evidence of zoonotic transmission of TB in northwestern Ethiopia. We did not identify a direct route of transmission between cattle and its owners. This is the objective of further investigations.

Situação da tuberculose em ovinos consorciados com bovinos leiteiros na região sudoeste maranhense

RESUMO: Objetivando conhecer a situação da tuberculose ovina no Maranhão, avaliaram-se 343 ovinos da região sudoeste do estado, 247 fêmeas e 96 machos, com idade acima de 6 meses, por meio do teste cervical comparativo (TCC), com inoculação de tuberculinas na região cervical direita. Cranialmente, injetou-se derivado proteico purificado (PPD) aviário; e caudalmente, PPD bovino, em doses individuais de 0,1 mL. Todos os animais apresentaram resultado negativo para tuberculose, entretanto, 65 ovinos apresentaram reação à tuberculina bovina superior à aviária. Para investigar a possibilidade de baixa sensibilização ou anergia em animais com tuberculose avançada, foi necropsiado um ovino caquético, idade acima de quatro anos, com resultado negativo ao TCC, porém, com reação à tuberculina aviária e linfonodos aumentados com consistência endurecida. Os resultados indicaram infecções por C. pseudotuberculosis, Actinomyces pyogenes, Staphylococcus aureus e Mycobacterium sp. A cultura e o isolamento resultaram em Pseudomonas aeruginosas e Bacillus sp. Não foram visualizadas estruturas bacterianas compatíveis com bacilo álcool ácido resistente (BAAR). Os resultados confirmam ausência de animais reagentes ao M. bovis, pressupondo inexistência da tuberculose em ovinos na região estudada.

Brucellosis and bovine tuberculosis prevalence in livestock from pastoralist communities adjacent to Awash National Park, Ethiopia

This cross-sectional study investigated the prevalence of brucellosis and bovine tuberculosis (BTB) in local cattle and goat breeds of Oromo and Afar pastoralist communities living in two distinct parts around the Awash National Park. A questionnaire survey was carried out to assess information on husbandry, milk consumption habits, and on knowledge-attitude-practice regarding both diseases. Among a total of 771 animals from all sites tested by comparative intradermal tuberculin test (CIDT) none were BTB reactors with the >4mm cut-off. Using the >2mm cut-off, individual apparent prevalence was 0.9% (95%CI: 0.23-3.56%) in cattle and 0.7% (95%CI: 0.12-3.45%) in goats. Herd prevalence in Oromia and Afar sites was 0% and 66.7% respectively in goats and 16.7% and 50% in cattle. Among the 327 animals tested by enzyme linked immunoassay for brucellosis, 4.8% (95%CI: 1.2-17.1%) of cattle and 22.8% (95%CI: 5.98-29.5%) of goats were reactors. Highest individual prevalence of both diseases was found in Afar settlements with brucellosis being as high as 50%. Respondent ethnicity was the only risk factor for brucellosis positivity in goats in the univariable risk factor analysis. Knowledge about the diseases was poor. Raw goat milk was regularly consumed by women and children, putting them at risk for brucellosis. This study highlighted an increased prevalence gradient of BTB and brucellosis from West to East along the study sites with high brucellosis individual prevalence and abortion rates among Afar settlements in particular.

Strain diversity of Mycobacterium tuberculosis isolates from pulmonary tuberculosis patients in Afar pastoral region of Ethiopia

Data on genotypic diversity of Mycobacterium tuberculosis complex (MTBC) is important to understand its epidemiology, human adaptation, clinical phenotypes, and drug resistance. This study aimed to characterize MTBC clinical isolates circulating in a predominantly pastoralist area in Ethiopia, a country where tuberculosis is the second leading cause of mortality. Culture of sputum samples collected from a total of 325 pulmonary TB suspects was done to isolate MTBC. Spoligotyping was used to characterize 105 isolates from culture positive slopes and the result was compared with an international database. Forty-four spoligotype patterns were observed to correspond to 35 shared-types (SITs) containing 96 isolates and 9 orphan patterns; 27 SITs containing 83 isolates matched a preexisting shared-type in the database, whereas 8 SITs (n = 13 isolates) were newly created. A total of 19 SITs containing 80 isolates were clustered within this study (overall clustering of 76.19%). Three dominant lineages (T, CAS, and Manu) accounted for 76.19% of the isolates. SIT149/T3-ETH was one of the two most dominant sublineages. Unlike previous reports, we show that Manu lineage strains not only constitute a dominant lineage, but are also associated with HIV infection in Afar region of Ethiopia. The high level of clustering suggests the presence of recent transmission that should be further studied using additional genotyping markers.