Contributions of village animal health workers to foot-and-mouth disease control in Cambodia.

Local animal health services in rural communities in Cambodia are mainly provided by village animal health workers (VAHWs), although the participation and contribution of VAHWs to livestock disease prevention are uncertain. The participation of the VAHWs as identified by their 'dropout rate' was examined in a desktop review in December 2020 of the national data on VAHWs recorded between 2011 and 2020. The contribution and involvement of VAHWs in disease prevention programmes were examined in a survey conducted between February and March 2014, then analyzed in the context of other surveys of VAHW knowledge, attitudes and practices. The survey involved guided group discussion with VAHWs (n = 198) from the two Cambodian provinces of Kampong Cham and Pursat. This study identified that VAHWs generated less than 22% of their annual household incomes from animal health services. Less than one-third had vaccinated livestock against foot-and-mouth disease (FMD), with none having vaccinated cattle every 6 months during the study period, and nearly half of the VAHWs having never vaccinated their own cattle against FMD. As no privately provided FMD vaccination services occurred in these communities, with all vaccines delivered through the government-subsidized programme, the findings confirmed that VAHWs only vaccinated animals against FMD when vaccines were made available by the Government. The desktop review found that the number of VAHWs in 2020 declined by more than 24% since 2017, and the proportion of female VAHWs was consistently low, with a mean of 8.26 (±1.019). These findings confirm findings from previous studies that identified considerable weaknesses in the VAHW system in Cambodia, particularly in contributing to FMD control. Cambodian animal health authorities require more effective policies to strengthen the current VAHW system, improving their services delivery; their retention as 'active'; their development of more sustainable roles with lower 'dropout' rates and the prolonged gender inequity. With the limited availability of government-subsidized FMD vaccination currently, extension programmes that engage VAHWs and farmers in seeking privately funded and delivered FMD vaccination that incorporates appropriate multivalent FMD serotype vaccines of high quality, delivered in small dose vials from a robust cold chain, is suggested. This strategy would assist VAHWs to contribute to the provision of private livestock vaccination services that are likely essential for sustainable FMD prevention and control in Cambodia.

Knowledge, attitudes and practices of smallholder farmers on foot and mouth disease control in two Cambodian provinces.

Food-and-mouth disease (FMD) is endemic in Cambodia. The control programme for FMD has relied on vaccination, with poor vaccination uptake by smallholder farmers becoming an increasing concern. A study to improve the understanding of farmer knowledge, attitudes and practices of FMD control and vaccination was conducted in two Cambodian provinces (Kampong Cham and Pursat). The aim was to identify opportunities to improve the livestock disease control programmes provided by both the government and private sectors. The survey comprised 300 smallholder farmers using a one-on-one interview technique and was completed between January to February 2014. Results identified that over two-thirds of the respondent farmers had not vaccinated their cattle over 2 years (2011-2013). Of those who did, most cattle were vaccinated either once a year or once every 3 years. A booster had never been administered. It was concluded that the FMD vaccine had only been administered through an unreliable and limited government vaccination programme, and private FMD vaccination services were not accessed in the study areas. FMD outbreaks occurred every year during the study period, with a morbidity rate of over 30%. Isolation of first infected cattle from the household herd was not practiced, with treatment identified as the first preference intervention. Farmers often assisted other farmers to restrain and treat infected cattle both before (57%) and after (43%) their own cattle were infected. This indicated that most farmers did not practice basic biosecurity measures and chose to report FMD outbreaks to the village animal health workers (VAHW), friends, neighbours and relatives in preference to government officials. It was concluded that poor knowledge of disease transmission and biosecurity, with low FMD vaccination coverage and a focus on treatment, contribute to regular FMD outbreaks in these communities. Improvement of FMD control requires the cooperation of villagers, VAHWs and village leaders in disease reporting, with either improved funding of government vaccination services or establishing a private FMD vaccination service. Training programmes for farmers on disease transmission, and the importance of biosecurity and vaccination, including information on the cost-benefits of treatment versus full fee bi-annual FMD vaccination, are required.

Effect of vaccine storage temperatures and dose rate on antibody responses to foot and mouth disease vaccination in Cambodia.

A field study investigated the effects of foot and mouth disease vaccine storage temperature for 7 days (frozen, refrigerated or held at ambient temperature) and dose (half or full dose) on the serological response to vaccination. It utilised a complete factorial design replicated on 18 smallholder cattle farms in three villages in Pursat province, Cambodia. Antibody responses from the 108 cattle involved were assessed by serological examination of blood samples collected at primary vaccination (day 0), at booster vaccination (day 30) and finally at 60 days post primary vaccination. Vaccination responses to the inactivated vaccine were assessed by testing for antibodies directed against FMD structural proteins in a liquid-phase blocking ELISA (LPBE test) and differentiated from responses to natural infection by examining antibody titres against non-structural viral proteins (NSPE test). LPBE results indicated that the mean log10 LPBE antibody titres of all experimental cattle increased from below protective levels at day 0 to protective levels at 30 days post primary vaccination, and increased further at 60 days post primary vaccination. Storage at ambient temperature for 1 week had no effect on antibody response to vaccination. However, freezing the vaccine for a week or use of a half dose resulted in significant reduction in titres at day 60 (P = 0.04 and P = 0.02, respectively). The results of this study reinforce the need to store FMD vaccines within the range recommended by the manufacturers and to adhere to the specified dosage instructions.