Epidemiology Investigation and Prevention of Canine Rabies in Yulin City
|School||Nanjing Agricultural College|
|Course||Preventive Veterinary Medicine|
|Keywords||rabies virus carrier rate antibody positive rate immune programme|
Rabies is a viral zoonotic disease. The virus is usually transmitted by a bite and invades the nervous system. The mortality of the disease is extremely high with nearly 100% deaths. In recent years the cases of rabies in human are increasing in China and the number of death due to rabies is the highest among key infectious diseases. Yulin city is one of the few prefectures with most human cases in Guangxi Zhang autonomous region which is one of the main epidemic regions in China.The occurrences of rabies in Yulin city rise year after year. The reason for this may due mainly to inappropriate vaccination procedure, lack of immunity monitoring, and poor immunization quality. Therefore, the compelling solutions to this problem in Yulin are to investigate the epidemic situation of canine rabies, work out a scientific vaccination programme, ensure the immunization quality, and find out effective prevention and control measures.An epidemiological survey was carried out to the cases found in canine and human in Yulin during the period from 1999 to 2005. It is found that the number of the cases in human has been increasing since 1999 and reached a peak of 78 cases in 2003, followed by a slight decline in number of cases. Similar situation was found in canine.Detection of rabies virus by reverse transcription-polymerse chain reaction (RT-PCR) was performed in 350 brain samples randomly selected from apparently healthy dogs from all over Yulin. The result showed 8.57 % of 350 samples tested positive to virus, with varying prevalence of virus carriers in different area. The prevalence of the virus carriers in dogs correlates to the morbidity of human rabies cases.The serological survey by ELISA assay found an average of 58 % of serum samples tested antibody positive to rabies from 700 samples obtained from all over Yulin, suggesting the anti-rabies positive conversion rate is low. The low antibody positive rate in dogs may be accounted for one of the reasons for the high morbidity of rabies in human. The canine antibody positive rates in the vaccinated ones are different in different counties investigated. It is found that the anti-rabies antibody positive rate in canine are adversely correlated with the morbidity of rabies in human in Yulin.An vaccination experiment was carried out in 100 two-month old healthy puppies. The puppies were divided into five groups stochastically with one group of puppie were injected with one dose of rabies vaccine, and the second group were injected with one dose of a 5-in-1 combination vaccine. The third group were injected with a 5-in-1 combination vaccine for one dose, followed by two boosts of one dose each at day 21 and 42 after the initial dose, respectively. The fourth group were injected with a 5-in-l combination vaccine for a dose, followed by a boost dose with rabies vaccine at day 21 after the initial dose. The fifth group of puppies were controls without vaccination. The levels of antibody against rabies in serum were monitored by ELISA. The result showed that the immunity of the rabies vaccine is better than that of the 5-in-1 combination vaccine for a single injection with an immune period of 6 months. The best immnune response was achieved by an initial injection with the 5-in-l combination vaccine followed by two boosts of the same vaccine at day 21 and 42, respectively. It is recommended that a vaccination programme with an initial injection of the 5-in-l combination vaccine followed by two boosts at 21 and 42 days after the initial dose be implemented in the whole region.