Dear colleagues,
This is Dr. Rafique from Bangladesh. I am working as Director (I/C) in SAARC Regional Leading Diagnostic Laboratory for PPR under Bangladesh Livestock Research Institute, Dhaka.
Goat farming is a common feature for the vast majority of Bangladesh rural households where on average four to five small stock is reared. The predominant breed is the Black Bengal, which is highly prolific with an average kidding rate 280 kids per 100 adult female goats. Bangladesh is one of the top ten goat
producing countries in the world. The vast majority (over 80%) of the sheep and goats in the country are owned by very poor marginalized peasant farmers (predominantly women) living in the rural and peri-urban areas who keep these animals for livelihood enhancement and storage of wealth in case of emergencies.
A number of studies on PPR have been undertaken in Bangladesh targeting prevalence estimates in some divisions of the country and the assessment of the efficacy of the conventional live attenuated and the thermostable vaccines currently in use. Findings reveal that the disease is caused by PPR lineage IV virus and is endemic in the country with no clear seasonality pattern. The Black Bengali goats were found to be more susceptible than other breeds and young animals 6-12 months of age are more severely affected by the disease, compared to adult and suckling animals. This is consistent with the findings associated with the disease in other parts of Asia and the world
in general except for variation in the lineage types. With regards to the PPR vaccine, the thermostable vaccine developed by the Bangladesh Livestock Research Institute (BLRI) was shown to retain potency and efficacy for 7-14 days at environmental temperature (20-40oC), while the efficacy of the conventional live attenuated PPR vaccine produced by same institute has been questioned by several field veterinarians and farmers. Live attenuated PPR vaccine was developed from local isolates collected from Meherpur district, where the disease was first identified in 1993. Thermostable PPR vaccine was developed from same seed of live vaccine by using trehalose. In 2011, available statistics from DLS showed that 2,173,509 representing 12.1% of the population at risk were vaccinated against the disease. This is very low compared to the recommended level of at least 75 - 80% vaccination coverage necessary to achieve national flock immunity that will
break the disease cycle. From the year 2010, data on disease incidence, mortality and vaccination coverage has been collated, mapped and documented by DLS in collaboration with the ECTAD Unit of FAO Bangladesh. However, a number of challenges still exist regarding effective control of the disease, which include poor funding for PPR control, insufficient vaccine production (3.4m doses were produced in 2011 against 10m production capacity), lack of adequate surveillance and paucity of manpower in the department to undertake mass vaccination program.
At this moment we are conducting a pilot project on PPR control in selected (2 districts, 5 villages) areas of Bangladesh. Firstly, a baseline survey was conducted door-to-door to know the exact number and age of goats for calculating requirement of exact vaccine dose and sero-surveillance samples. Awareness campaigns were done by meeting and poster presentation. Locally produced conventional vaccines were used for mass vaccination in 3-5 spots in each village for ensuring 100% coverage. Pre and post vaccination antibody will be monitored 0, 21, 180, 270 and 360 days. Sero-surveillance samples collected before vaccination. for ensuring quality vaccine, vaccines were directly
collected from production unit, transported with cool-chain and used within two hours after reconstitution. We found in our previous experiment, two hours is the maximum time after reconstitution for getting maximum antibody and providing quality vaccination. it needs to work on how it can be increased the time after reconstitution of the PPR vaccine. It is difficult to finish the 100 doses vial after reconstitution within two hours, if there is no mass gathering of goats in the village. We discarded remaining doses after two hours. It is better to use 50 doses vial, if available.
Currently, Bangladesh is developing PPR control strategy action plan. It seems a progressive control strategy using intensive surveillance and phased vaccination program over 2-3 years will ensure the attainment of at least 75% immune population of small ruminants in Bangladesh necessary to
block the epidemic cycle of the virus. Thereafter, in a few more years, it is possible to eradicate the remaining pockets of the disease using the OIE pathway (similar to Rinderpest eradication pathway) if the effort is sustained. This is a rare window of opportunity for global PPR eradication.
Best Regards