The Diagnosis Of A Fowlpox Virus Mixed Infection With Staphylococcus Aureus

Fowlpox virus, the prototype of the Avipox virus genus, is the best-studied species, and caninfect poultry and a variety of rare birds, and causes common viral disease of poultry. Fowlpox iscaused by fowlpox virus, which is an acute, contagious disease, and clinically this disease isusually divided into three type: cutaneous, mucous membranes and mixed. The disease iswidespread throughout the world, the mortality is not pretty high when poultry flocks infect withfowlpox virus (FPV), if there are some secondary infections like some infectious diseases(such asinfectious rhinitis), parasitic diseases and the occurrence of bacterial mixed infections (such asStaphylococcus aureus disease). In addition to poor sanitary conditions, malnutrition cases, thesemay promote the occurrence and aggravation of the disease, also can cause massive death, whichbring enormous economic losses of poultry industry.Staphylococcal in Chickens is an infectious disease caused by pathogenic Staphylococcusaureus. The main clinical manifestations include acute sepsis, arthritis and chicks Omphalitis, skinnecrosis, periostitis and arthritis and other types. Staphylococcus aureus is mainly involved inchicken and turkey, various species and ages are susceptible (including chicken embryo), but thedisease breaks out frequently in the40-60day-old chickens. The animal susceptibility ofStaphylococcus aureus is related to a variety of factors, and easy to infect with other diseases suchas fowlpox, avian E. coli disease, Marek’s disease. Therefore, Staphylococcus aureus is one of thegerms that is difficult to overcome currently.November2013, a large breeder in Tongliao City of Neimenggu, which raises100,000broilerbreeders, about5000breeders were dead when we got this case, the incidence rate of about10%,the mortality rate was5%. The main clinical symptoms of the disease include dead chickenswhich are extremely weight loss; the back, neck, under the wings and little hairless area could seelarge smallpox, smallpox scab; mouth, eyelids, nose sizes are visible in dark red and brownsmallpox. Meanwhile, there are a lot of blood oozing fluid retention from craw to the chest abdomen, under the inner thighs and wings of the dead chickens, we can see that the skin presentsdark red, purple or purple-brown, a sense of volatility, partial shedding feathers. For furtherdiagnosis, we identify this case in terms of histopathology. The results showed that the mostobvious cases of lesions in the skin and brain, skin and vascular congestion with lymphocytes,heterophilic granulocyte infiltration; portion of the skin lesion biopsy shows a large number ofnewly generated fibroblasts and capillaries, and inflammation cell infiltration. Brain perivascularinflammatory cell infiltration. Other organs also see different levels of pathological changes, butthese are general lesions.In order to further clarify the reasons for the case of death, the death of chickens in this studyconducted a systematic analysis of laboratory diagnosis. DNA was extracted after grindingepidemic materials, we detect this disease via PCR by using FPV specific primers, which isintegrated with REV fragment, in our laboratory. Amplification results were positive, it isapproved that the FPV is integrated with REV fragment. We cultured and isolated virus withchicken chorioallantoic membrane inoculation, the plaques were stable after three generation,PCR detection was positive, EID50detected the viral titers, the virus infected primary chickenembryo fibroblasts (CEF), the cells presented typical "pull mesh" after five generation. Finally,sequencing results showed that the isolates with Chinese isolates (Genbank accession number:GQ415646) are very closely, the amino acid and nucleotide homology up to100%. The isolatewas identified as FPV.Meanwhile, we isolated and purified single colony, we could see bunches bacterium likeGram-positive cocci (G+) after Gram staining.5%ordinary rabbit blood agar,37℃cultured24h,blood agar colonies of hemolytic seen around. Biochemical characterization of pathogens, bacteriacan ferment glucose, lactose, maltose, sucrose and mannitol; coagulase test, catalase test, MR arepositive; does not produce H2S, consistent with the quality control strains biochemicalcharacteristics, determine the strains of Staphylococcus aureus. Susceptibility testing foundsensitive to vancomycin and chloramphenicol.Furthermore, the animal tests demonstrated similar clinical symptoms to natural infections,we further confirmed that this disease was caused by FPV secondary infection of Staphylococcus.