Diagnostic studies on some infectious diseases affecting skin in bovine and buffaloes calves at EL-Dakahlyia province, Egypt

Abstract

Background: Infectious cutaneous diseases are major threat of bovine and buffaloes calves in Egypt and cause huge economic impact as a result of hide damage, decreased growth rate and mortality rate. Material & methods: A retrospective study was conducted between October 2016 and January 2020 to identify different infectious diseases affecting skin in 5000 examined bovine calves from ten local dairy farms located at El-Dakahlia province. Clinical signs, morbidity and mortality rates were reported. Gross examination of lesions was applied. Skin biopsies were collected from lesion and surrounding areas and part of these samples fixed in 10% buffered formalin for routine hematoxylin and eosin (H&E) staining. Periodic acid Schiff stain (PAS) and immunohistochemistry (IHC) were also applied for diagnosis. The other part of skin samples was kept at-80°C for viral isolation by real time- polymerase chain reaction (RT-PCR). Results: Four infectious diseases were detected in 2220 examined bovine calves out from 5000 (44.4%) including warts (150 cattle calves), FMD (1500 cattle calves and 500 buffaloes calves), LSD (45 cattle calves and 5 buffaloes calves) and ring worm (20 cattle calves). Special staining using PAS was sufficient to diagnose ring worm. Histopathology and IHC diagnosed few cases infected with LSD that showing inclusion bodies in 10 out of 50 calves (0.2%). No inclusion bodies were seen in any infected specimens with FMD or papillomas. Viral nucleic acids of FMD, papillomatosis and LSD virus were detected in infected skin samples. Conclusion: cattle calves showed higher susceptibility to these infectious skin diseases than buffalo calves. FMD caused higher morbidities than in other diseases. Mortalities were reported with FMD and LSD infection. Histopathology was not sufficient to diagnose viral infection. IHC cannot diagnose LSDV in all infected cases. PCR should be used for accurate detection LSD, FMD and papilloma viral nucleic acids in skin samples.