Study on the transmissibility of the virus caprine arthritis encephalitis

Abstract

The etiologic agent for caprine arthritis encephalitis (CAE) is classified as belonging to the family Retroviridae, genus Lentivirus, promoting the onset of incubation and slow evolution in several species of animals with degenerative and / or inflammatory diseases of various tissues. Lentiviruses are generally non-oncogenic, but they are species-specific, and they are known to have high mutation rates, which results in genotypic and phenotypic diversity. The infection of goats by the caprine arthritis-encephalitis virus (CAEV) is considered to be a life-long state, as the virus persists in the organism throughout the animal's entire life, with the possibility of viremia being constant. The lentivirus infection, which is generally persistent and asymptomatic, can cause multisystem diseases that are generally chronic in their development, with a progressive worsening of the lesions, weight loss, weakness and eventual death. CAEV can induce four clinical forms of the disease: articular (chronic arthritis), mammary (indurative mastitis), pulmonary (acute progressive pneumonia) and nervous (leukoencephalomyelitis).Vertical transmission can occur, it has been observed seroconversion of the goats that were separated immediately after birth and received colostrum and pasteurized cow milk. The transmission via the placenta or by natural mating in goats has not been proven indisputably. But the proof of the presence of lentivirus in goat semen diagnosed by nested-PCR increases the chance of transmission of lentivirus by natural mating and artificial insemination.The aim of this study is to evaluate the transmissibility of the caprine arthritis encephalitis virus through the placenta and semen (vertical transmission). It is known that few studies assessing the reproductive behavior in the transmission. With the addition of molecular biology techniques and immunodiagnostic, this study will achieve more accurate and reliable data for the transmissibility of the virus and help to determine actions necessary to control the disease recommended in the National Health Goats and Sheep (PNSCO) of the Ministry of Agriculture, Livestock and Supply.In the experiment, the animals will be divided into two groups: Group 1 (Influence of semen in transmission) that will consist of six females to negative arthritis encephalitis virus to be inseminated with semen positive to the virus and Group 2 (Influence of the placenta or vertical transmission) that will consist of six females positive for arthritis encephalitis virus to be inseminated with semen negative for the virus. All mothers are kept together in a stall for each group during six months until the birth collecting whole blood to perform PCR, nested-PCR and ELISA and immunodiffusion in agar gel every 15 days. And all the kids will also be monitored for a year collecting whole blood to perform PCR, nested-PCR and ELISA and immunodiffusion in agar gel every 30 days. The verifications of the influence of the presence of the virus in the semen on the results obtained in the determination of serum CAEV antibodies by AGID and ELISA, and the virus detection by nested-PCR study in animals shall be conducted by two proportions test, with approximation by normal distribution, using a significance level of 5%. (AU)