Consequence of Avian Influenza Transmission to Dairy Cattle and Associated Risk of Human Infection Through Virus Contaminated Milk: A Brief Report

Correspondence author: Tapas Goswami, Former Scientist Emeritus (IVRI, ICAR), Presently Professor Department of Veterinary Microbiology, Institute of Veterinary Science and Animal Husbandry, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, 751030, Odisha; Email: tapasgoswami@soa.ac.in; goswami.tapas@gmail.com Recently in March 2024 scientists have observed that dairy cattle from USA have been infected with avian influenza virus. The live virus particle was detected in the milk sample and nasal washing of affected cow. How the infection has gone to cow is unknown and can’t be confirmed. Role of wild migratory birds in virus spreading has been predicted. Presence of live virus particles in milk highlights the public health risk. The infected cow did not show any specific symptoms except reduced feed intake, abrupt drop in milk yield. Milk of affected cow was colostrum like thickened creamy yellow. Infection was recorded in older cows mostly during middle or late lactation. Most of the animal recovered. Virus infection in two dairy farm workers has confirmed the transmissibility of the virus to human through direct and close exposure to raw milk and secretions from the infected dairy cows. The course of disease in those affected farm workers was mild and symptoms subsided early with oseltamivir taken orally for five days. As per experts’ opinion pasteurization is safe for virus-containing milk for human consumption. However, milk from cattle is the source of infection so we must remain vigilant for early detection.