Menangle pararubulavirus

Menangle pararubulavirus is a zoonotic virus that belongs to the genus Rubulavirus within the family Paramyxoviridae. It was first identified in 1997 during an outbreak among pig farms in Menangle, New South Wales, Australia. The virus is notable for its ability to cross species barriers, having been documented to infect both pigs and humans, leading to concerns about its potential for causing widespread disease.

Etiology

Menangle pararubulavirus is an enveloped, single-stranded, negative-sense RNA virus. Its genome encodes several structural and non-structural proteins that play roles in virus replication, host cell entry, and immune evasion. The virus is closely related to other members of the Rubulavirus genus, such as the mumps virus, but has distinct features that facilitate its zoonotic transmission.

Epidemiology

The primary reservoir for Menangle pararubulavirus is believed to be fruit bats, specifically species within the genus Pteropus, also known as flying foxes. These bats can harbor the virus without showing signs of illness and play a crucial role in its natural history and transmission cycle. The virus can be transmitted from bats to pigs, where it can cause significant outbreaks characterized by reproductive failures, including abortions and stillbirths. Human cases of Menangle virus infection have been linked to direct or indirect contact with infected pigs or their environments.

Clinical Manifestations

In pigs, Menangle virus infection can lead to a range of reproductive issues, including infertility, mummified fetuses, and congenital abnormalities in newborn piglets. Infected sows may exhibit flu-like symptoms, such as fever and lethargy, though these are not always present.

Human infections with Menangle pararubulavirus are rare but have been documented. The reported cases in humans have presented with flu-like symptoms, including fever, chills, and muscle aches. In some instances, a rash or encephalitis, an inflammation of the brain, has also been reported. However, due to the limited number of human cases, the full spectrum of disease in humans is not well understood.

Diagnosis

Diagnosis of Menangle virus infection can be challenging due to the nonspecific nature of the symptoms. Laboratory tests, including polymerase chain reaction (PCR) assays, serology, and virus isolation, can be used to confirm the presence of the virus in both humans and animals. These tests are essential for distinguishing Menangle virus infection from other diseases that cause similar symptoms.

Prevention and Control

Preventive measures against Menangle virus infection are primarily focused on reducing the risk of transmission from bats to pigs and from pigs to humans. These include implementing biosecurity practices on pig farms, such as securing food sources to prevent access by bats, and using personal protective equipment when handling pigs or pig products. There is currently no vaccine available for Menangle virus for either pigs or humans.

Public Health Implications

The emergence of Menangle pararubulavirus highlights the ongoing risk of zoonotic diseases and the importance of surveillance and research on viruses that can cross species barriers. Understanding the ecology and transmission dynamics of such viruses is crucial for developing effective prevention and control strategies to protect animal and human health.