Abattoir based Sero-Survey of Mycobacterium avium Subspecies Paratuberculosis in Bovines in District Faisalabad-Pakistan

Livestock being a major sector contributes 11% in the GDP which is more than the share contributed by the crop sector (i.e., 10.3%) thus playing a vital role in the economy of Pakistan (Chandio et al., 2016). The causative agent of paratuberculosis is Mycobacterium avium subsp. Paratuberculosis (MAP). Animals affected with paratuberculosis exhibit clinical signs such as reduced milk production, intermittent diarrhea, chronic weight loss and eventually results in death of the animals. On post-mortem examination, granulomatous lesions may be observed in liver and lymph nodes of the affected animals (Singh et al., 2016).

Paratuberculosis effects all ruminants species including cattle and calves less than six months of age are more susceptible as compare to other age group while it has been estimated that a single exposure of infection can result in the development of the disease in one third of the exposed calves (Windsor and Whittington, 2010). In older animals due to the well-developed immune system the production of disease requires higher doses of MAP (Hines II et al., 2007). Paratuberculosis is most commonly transmitted via ingestion of contaminated colostrum, milk and feces, which are contaminated by MAP either by intra-mammary shedding or indirectly. They further reported that MAP is also transmitted vertically or transplacentally (Kirkeby et al., 2016; Van Kooten et al., 2006).

Paratuberculosis being a major threat to meat and dairy animals has a global economic importance and its control poses a global challenge for the livestock sector (Hines II et al., 2007). Furthermore some research studies indicated its potential as public health hazard by demonstrating an association between MAP and human Crohn’s disease (Feller et al., 2007; Naser et al., 2004). The control strategies of paratuberculosis are mainly based upon screening and slaughtering policy and adopting good management practices (Garry, 2011). This study was designed to evaluate the prevalence of paratuberculosis in bovines in Faisalabad-Pakistan.

The present study was designed at a slaughter house located in city area of district Faisalabad, which is the 3rd largest city of Pakistan with a human population of 2,506,595 and is located with GPS coordinates of 31° 25’ 15.7620’’ N and 73° 5’ 21.4584’’ E. Blood samples (n=455) were randomly collected from slaughterd cattle (n=172) and buffaloes (n=283) from slaughter house in district Faisalabad. A questionnaire containing history of slaughtered animals, age, BCS, sex and body weight was filled. The blood samples were collected directly from jugular vein, all tubes were places in ice bags and immediately transported to Bacteriology Lab, Institute of Microbiology, University of Agriculture, Faisalabad for further analysis.

The serum was separated by centrifugation @ 1500 RPM as described by Adkins et al. (2002). Sera were stored at -20°C for a temporary period. Then, serum samples were thawed at room temperature and antibodies against MAP were detected by using a commercial ELISA kit (LSI, Vet, Ruminant Serum paratuberculosis Screening, France).

The data were analyzed by Chi Square test using SPSS 20.0 version and odds ratios were also calculated using OpenEpi statistical software (version 3.01).

In this serological study MAP was not detected significantly (p>0.05) in cattle and buffaloes. Out of 283 blood samples collected from buffaloes, 90 samples (31.8%) were found positive for paratuberculosis while out of 172 blood samples collected from cattle, 54 samples (31.4%) samples reacted positively for paratuberculosis.

A total of 68 samples were collected from cattle under 4 years of age and 23 (33.8%) were positive for MAP and for buffalo under same age, 115 samples were collected and 34 (29.6%) were positive for MAP. A total of 18 samples were collected from cattle having age >6 years, and 6 (33.3%) were positive and 33 samples were collected from buffaloes with same age and 10 (30.3%) were positive for MAP. Seropositivity was not different among different age groups of cattle (chi square=0.420, df=2, P=0.809) and buffaloes (chi square=0.620, df=2, P=0.733). The seropositivity was not dependent upon age groups (chi square=0.046, df=2, P=0.977) as shown in Table I. Paratuberculosis has a significant effect on body weight, Seropositivity was significantly (p<0.05) higher in animals under 300kg body weight and decreased significantly (P<0.001) with the increase in BCS of animals as shown in Table II and III, respectively. Gender of the animals was not significantly associated with the occurrence of the disease (x2=0.227, df=1, P>0.05) (Table IV).

Values with different superscripts differ significantly (chi square=59.381, df=2, P<0.001)

Paratuberculosis is an infectious disease of dairy animals and is also zoonotic in nature (McNees et al., 2015). Submandibular edema, emaciation, progressive weight loss and chronic diarrhea are the signs which are shown by infected dairy animals (Garcia and Shalloo, 2015; Mortier et al., 2015). Antibodies can be detected against MAP using indirect ELISA (Vazquez et al., 2013). In the present study, blood samples were collected from a slaughterhouse located in the urban area where the animals were brought for slaughtering from periurban and rural areas. This is convenient sampling (Etikan et al., 2016) but the results revealed the prevalence of the disease in nearby areas and its association with other factors including age, sex, BCS and body weight.

In the present study overall prevalence of the paratuberculosis in cattle and buffaloes was found to be 31.8% and 37.8%, respectively; which is higher than the findings of McKenna et al. (2004) where the prevalence recorded in culled dairy cattle in abattoir was 16.1% (95% CI: 13.8 to 18.3%). Singh et al. (2008) reported a lower prevalence of 2.71% in Punjab, India. A low individual level prevalence (4.03%) than our study was also recorded in dairy herds in Spain (Diéguez et al., 2007), 28.6% herd in dairy cattle was documented in Cyprus (Slana et al., 2009), 2.77 % in Slovenia (Ocepek et al., 2002), 18% in dairy cattle in Belgium (Boelaert et al., 2000), 3.07% in Urmia state of Iran (Yousof et al., 2003) and 1.6% to 55% in the united States of America (Fernández-Silva et al., 2014).

In the present study, seropositivity was not dependent upon age groups (chi square=0.046, df=2, P=0.977). The results of our study are similar with the study conducted by Vazquez et al. (2013) in Spain wherein they found a high prevalence of 16.5% at 3-4 years and low prevalence at 7-8 years of age. Two years old calves have been reported to be effected by paratuberculosis (Stabel, 2006) but no significant difference has been recorded among age different groups with reference to paratuberculosis also not significant (Cetinkaya et al., 1996) which is similar with our finding. As per findings of Muskens et al. (2003) the prevalence of the paratuberculosis is not effected by season or months of year.

Paratuberculosis has a significant effect on body weight, seropositivity was significantly (p<0.05) higher in animals under 300kg body weight in the present findings which are similar with the findings of Mato et al. (2017) where animals also lose body weight as the disease progresses. According to Johnson et al. (2001) loss of body weight is the sign of paratuberculosis. BCS is in inverse relation with the onset of the disease in the present findings and same were observed by Lombard et al. (2005). But the present findings are not in accordance with McKenna et al. (2004), who did not find any association of BCS with paratuberculosis.

Gender of the animals was not significantly associated with the occurrence of the disease. Both male and female animals were equally susceptible for paratuberculosis in the present study. But our findings are not in accordance to Verdugo et al. (2014), female animals were more positive than male animals in their findings. This is because MAP multiplies fast in erythritol sugar found in uterus in the females. In the present study, male animals are mostly slaughtered at slaughter house and also due to lack of awareness to the farmers, female animals are still standing at farms in weak emaciated conditions without good productivity.

In conclusion, body weight and body condition score of the dairy animals are positively associated with occurrence of the disease while age, sex and species are not significantly affected by paratuberculosis. The disease imposes huge economic losses to the dairy farmers in reducing milk yield, weak calves, loss body weight and delayed calving, so the data of the present study will not only help in screening of animals through ELISA but will be instrumental in future for isolation of MAP to make a vaccine against paratuberculosis using local isolates.

Authors declare that there is no conflict of interests regarding the publication of this article.