MATERIALS AND METHODS

The present study was conducted during the year 2012-2013 in the state of Assam. A total of 918 goat serum samples were collected from five districts of Assam (Jorhat, Darrang, Nalbari, Kamrup and Barpeta ) and animals were not vaccinated against PPRV at the time of sampling. The samples were analyzed using competitive ELISA (cELISA) kit as per method described (Singh et al., 2004a). Samples with Percentage Inhibition (PI) of $40% were considered positive for PPR specific antibodies.

The apparent and true prevalence were calculated as described elsewhere (Balamurugan et al., 2014) and the confidence interval (95% CI), Mean±SE and χ² test were estimated using Statistical Analysis System (SAS) software version 9.3 package (SAS India Ltd., Mumbai).

RESULTS AND DISCUSSION

Assam is a North-Eastern Indian state located in the Eastern Himalayas and shares international border with Bhutan and Bangladesh. The majority of residents of Assam carry out backyard farming as one of their main socioeconomic activity. The main livestock species maintained are goats (6.16 million), sheep (0.23 million), cattle (10.3 million) and pigs (1.64 million). The PPR is considered as an emerging/re-emerging disease in the state. In our earlier report, we have investigated a PPR outbreak in the Indo-Bangladesh border area of Tripura state, where in the virus strain involved in the outbreak was found to be lineage IV and is closely related to Bangladeshi strains (Muthuchelvan et al., 2014).

The present study investigated the seroprevalence of PPRV in goats from five districts of Assam. Since goat meat is preferred in the state, goat rearing is practiced widely. At the time of sampling, all the five districts were not performing vaccination against PPRV. In the earlier study, the presence of PPRV was confirmed by s-ELISA and PCR from three districts viz., Kamrup, Nalbari and Jorhat (Balamurugan et al., 2014). A total of 918 goat serum samples were randomly collected mainly from rural areas. District-wise and age-wise data are presented in Table 1. The overall prevalence of PPR in the region was13.18% (CI: 5.54-20.82) across five districts, with a high prevalence in two districts, (Kamrup (22.65%), Nalbari (22.22%)) and low prevalence in Barpeta (3.25%) district indicating wider circulation of PPRV in this region.

Table 1:	Seroprevalence of PPRV in goat population of five districts of Assam between 2012 and 2013

The age-wise distribution revealed that the prevalence rate was higher in >6 months group (15.79%, CI: 10.81-20.77) than in <6 months group (12.32%, CI: 3.48-21.16 ). In a previous study, Balamurugan et al. (2014) reported a prevalence rate of 18.07% in goats from Assam with a limited number of samples (n = 105). The present study carried out with moderate number of samples (n = 918), which showed overall prevalence rate of 13.18% which is in agreement with the overall prevalence of 11.63% for the entire North-Eastern region (Balamurugan et al., 2014). However, this rate is much lower to the national prevalence rate of 32.4-46.11% in goats (Balamurugan et al., 2014, 2011; Raghavendra et al., 2008; Singh et al., 2004b). The possible reasons for the lower prevalence in Assam may be due to hilly topology of the state and natural restrictions on animal movements. Overall, the present study confirms the endemicity of the PPR situation in the state of Assam and the information presented here will be useful during the implementation of the control program.

ACKNOWLEDGMENTS

The authors are thankful to the Vice Chancellor, Dean and Director Research (Vet.), College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-22 and the Director, North East Regional Disease Diagnostic Laboratory (NERDDL), Guwahati, for necessary help and facilities provided during the study.