Foot and mouth disease (FMD) is an acute, highly contagious viral disease of cloven footed animals. It is known to be endemic in India, with periodic outbreaks occurring in different geographical areas of the country. This study was conducted to investigate the presence of FMD virus (FMDV) in reported FMD-suspected cases and the secondary bacteria known to accompany FMD and to find the reason for high mortality rate. Blood samples were collected from affected animals of Shekhupur Raura village of district Bulandsahar and examined for presence of antibodies against FMDV. The possible common sources of the outbreak might be the introduction of infected cattle and buffaloes from the cattle market and commingling of animals with those of infected neighboring villages. As mass vaccination of animals (cattle and buffaloes) against Foot and mouth disease in Uttar Pradesh is going on, the occurrence of FMD in this area is a matter of great concern. This report appeals to the national and state authorities to impose strict regulations related to livestock movement and further improve monitoring and surveillance programme.
Foot and mouth disease (FMD) is highly contagious disease of the cloven-hoofed domestic and wild animals leading to significant economic losses to dairy industry and restriction in international trade of animals and animal products (OIE, 2010; Verma et al., 2012; Chakraborty et al., 2014). The disease is caused by Aphthovirus of Picornaviridae family and characterized by high fever, formation of vesicles in the mouth, teats and feet, profuse salivation (Thomson, 1994; Chakraborty et al., 2014) with almost 100% morbidity (OIE, 2010) and mortality may reach upto 50% in calves, when the virus replicates in heart muscles of claves (Gulbahar et al., 2007; Verma et al., 2008). The virus has seven serotypes (O, A, C, Asia-1, SAT-1, SAT-2 and SAT-3) but in India only four serotypes (O, A, C and Asia-1) are prevalent (Verma et al., 2012). FMD is endemic in India and is often underreported either due to its endemicity and the fact that it is not associated with high mortalities in adult susceptible animals, as such it is not considered as an important livestock disease among animal owners or farmers (Verma et al., 2012). The aim of the present study is to investigate the presence of FMD virus (FMDV) in reported FMD-suspected cases and the secondary bacteria known to accompany FMD and to find the reason for high mortality rate.
Materials and Methods
Study Area, Animals and their Management
The FMD outbreak in cattle and buffaloes was suspected in March, 2015 in the Shekhupur Raura village of district Bulandsahar located in Uttar Pradesh, India (Fig. 1). The livestock population of the affected village was around 5000 including cattle, buffaloes, goats and pigs at the time of incident. The animals were stall fed and had access to water twice/thrice a day.
Fig. 1: Uttar Pradesh Map showing the location of Bulandsahar district
History, Clinical Examination and Data Collection
Animals were examined by the experts from Uttar Pradesh Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishwavidyalaya Ewum Go-Anusandhan Sansthan (DUVASU), Mathura, India, along with Veterinary Officers of Animal Husbandry Department, Uttar Pradesh. Animals were showing clinical signs such as pyrexia (high rectal temperature more than 1050F), vesicles on gums, dental pads, tongue, foot and udder, increased salivation, anorexia and reluctant to move.
The specimens (vesicular epithelium from tongue and gums) were collected in 50% phosphate buffer saline-glycerol (PBS-glycerol) (Kitching and Donaldson, 1987), while blood samples were collected in vacutainers from affected animal and brought to laboratory in cold chain.
Vesicular epitheliums were sent to Central Laboratory, All India Co-ordinated Research Project on FMD, Indian Veterinary Research Institute, Mukteswar, Nainital, India for confirmation of FMD serotypes. The sera samples were screened for the presence of antibodies against foot-and-mouth disease virus using DIVA-ELISA kit provided by project directorate on foot and mouth disease, Mukteswar, Nainital as per the manufacturer’s protocol.
Result and Discussion
Out of 87 animals (cattle and buffaloes) that were physically examined in the affected village, 16 (18.4%) animals showed clinical signs and lesions suggestive of FMD. The principal clinical signs were fever, salivation and lameness. Mouth lesions include erosions and ulcers on tongue, dental pad etc. (Fig. 2 and 3).
|Fig. 2: Ruptured Vesicle on dental pad of cattle||Fig. 3: Ruptured Vesicle on lower jaw of cattle|
Foot lesions comprised of erosions on the interdigital spaces and the coronary bands (Alexandersen et al., 2003; Teifke et al., 2012; Yoon et al., 2012; Chakraborty et al., 2014). Some of the affected animals especially cattle showed foot lesions and, in most cases, healing mouth lesions where also observed. Few animals were died during the outbreak in the affected area. Results of DIVA analysis also showed the presence of antibodies against FMDV using DIVA-ELISA. For effective control of FMD, outbreaks should be detected at an early stage and persistent infections should be recognised to prevent further transmission of the virus (Longjam et al., 2011). The presence of clinical signs coupled with confirmation of presence of antibodies against FMDV from animals of the affected area confirmed that the majority of the animals in this area had been infected by FMDV. Due to the foot lesions, which are characteristic of FMD, some animals were observed as having difficulties in moving; this was previously reported by Hunter, 1997.
In the present investigation, heavy mortality was reported in the animals, who were not vaccinated against FMD, while the mortality was very low in vaccinated animals. Incubation period for FMD remain largely unknown for field outbreaks or around 2-13 days (Coetzer et al.,1994) as against less than 24 hrs after experimental inoculation (Timoney et al., 1988). As the transmission of disease is rapid mainly through aerosol (Alexandersen et al., 2003; Chakraborty et al., 2014) and/or contaminated feed and water, the isolation of affected animals and vaccination of apparently healthy animals (Orsel and Bouma, 2009; Amal et al., 2011) prevents the spread of the disease to further area by removing the chain reaction from one animal to another.
During the investigation of the outbreak in the Bulandsahar district, a discussion with local people in the area revealed that round the year there is purchase of high yielding animals from neighboring districts as well as states, which mingles with local herds of cattle and buffaloes (Sharma et al., 1991). Since, Bulandsahar district of Uttar Pradesh is one of the largest milk producing districts in the state having large number of dairies, where animals are frequently replaced by input from neighboring states viz., Punjab, Haryana and Rajasthan resulting in the frequent turnover in their population. Furthermore, vaccinations where not conducted in some of the animals within the affected area. Villagers also revealed that cattle traders usually pass by the villages on their way home from these markets with their animals. During this time, the traders’ animals interact with the local animals. During the marriage, cattle and buffaloes are usually used as gift with bride. Intermarriages are also common on the borders and cattle are usually used for payment of the bride. This also entails movement of animals from one family to another. In addition, pockets of farmers deliberately do not vaccinate their animals.
This study has detected the presence of antibodies to FMDV in the serum samples collected from the affected animals. Furthermore, clinical signs and laboratory tests suggested that it was outbreak of FMD in Bulandsahar district. This study could not conclude the sources of this outbreak, although information on the ground indicated that this could be from movement and interaction of animals from neighboring districts or states. It is also recommended that animal traders should be sensitised on the potential risk of transmission of FMDV among animals. Restriction of animal movement along with identification and the monitoring of animal movements are necessary to identify the cross-border movements and market chain interactions of ruminants must be enforced to minimise further trans-boundary transmission of the disease. This could be done by setting up more veterinary camps and increasing the number of veterinary staff in FMD high-risk areas.
Authors are highly thankful to Dean, College of Veterinary Science and Animal Husbandry, and Hon’ble Vice Chancellor, Uttar Pradesh Pandit Deen Dayal Upadhayay Pashu Chikitsa Vigyan Vishwavidyalay Evum Go-Anusandhan Sansthan (DUVASU), Mathura, India; for providing all the necessary support and facilities for conducting this investigation. Authors wish to thank Chief Veterinary Officer, Bulandsahar and other Veterinary Officers of the district for providing help in disease investigation. Authors are also thankful to Project Director, All India Co-ordinated Research Project on Foot-and-Mouth disease, for providing the diagnostic kits and necessary facilities in conducting this study.