Officials announced New Zealand’s first case of rabies on Thursday, in a person who contracted the virus overseas.
So what is rabies, and how concerned do we need to be?
To start: the Ministry of Health and Te Whatu Ora (Health New Zealand) say there is no risk to the public from the case. New Zealand does not have rabies in either its animal or human populations, and this case does not change our rabies-free status.
What is rabies?
Rabies is a vaccine-preventable, zoonotic virus that affects the central nervous system.
Person-to-person transmission is “extremely rare – almost unknown”, Director of Public Health Dr Nick Jones says.
Once symptoms appear, rabies is virtually 100% fatal, according to the World Health Organisation (WHO).
In up to 99% of cases globally, dogs are responsible for rabies virus transmission to humans – however, the virus can affect domestic and wild animals.
The Mayo Clinic says any mammal can spread the rabies virus, but animals more likely to spread the virus to people include: cats, cows, dogs, ferrets, goats, horses, bats, beavers, coyotes, foxes, monkeys, raccoons and skunks.
Internationally, children between the age of 5 and 14 years are “frequent victims”, WHO says.
What does rabies do?
The incubation period for rabies is typically two to three months, but can vary from one week to one year – depending on where the virus entered the body, and the viral load.
Epidemiologist Professor Michael Baker says this is because the virus has to travel along your nerves to your brain, which can take months.
Initial symptoms can include fever, pain, and unusual or unexplained tingling, pricking or burning sensations at the wound. As the virus moves to the central nervous system, “progressive and fatal inflammation” of the brain and spinal cord develops.
WHO says there are two forms of rabies.
“Furious rabies” results in hyperactivity, excitable behaviour, hallucinations, lack of co-ordination, hydrophobia (fear of water) and aerophobia (fear of drafts or of fresh air).
Death occurs after a few days due to cardio-respiratory arrest.
Paralytic rabies, accounting for about 20% of the total number of human cases, is a “less dramatic” and usually longer course than the furious form.
Muscles gradually become paralysed, starting from the wound site. A coma “slowly develops” and eventually death occurs, according to the WHO.
Where does rabies occur?
Rabies is present on all continents (except Antarctica), and more than 95% of human deaths occur in Asia and Africa, WHO says.
However, rabies cases are “rarely reported” and registered cases “differ greatly from the estimated burden”.
Rabies is considered a neglected tropical disease, that predominantly affects marginalised, poor and vulnerable populations.
In the Americas, haematophagous bats (those which feed on blood) are the major source of human rabies deaths, as dog-mediated transmission has been “largely interrupted”.
Bat-mediated rabies is also an “emerging” public health threat in Australia and Western Europe, a WHO resource published in January says.
Globally, it’s estimated rabies costs US$8.6 billion every year.
What happened in the New Zealand case?
The person, a traveller who contracted the virus overseas, was notified as having suspected rabies when first admitted to hospital in early March, the country’s lead health agencies say.
They were managed with “full infection control measures” while at Auckland City Hospital, and at Whangārei Hospital where they were first diagnosed.
The person died from the disease last week.
If you’re travelling
Professor Nick Wilson, in University of Otago’s department of public health, says it is important people travelling overseas are aware of the risks in the country they’re travelling to, including things like rabies.
If people are bitten or scratched by an animal in a country where rabies is common, they need to seek medical attention as soon as possible, as there’s an immunoglobulin and a vaccine people can get.
Baker echoed this, saying if you think you’ve bitten by an animal it’s important to get post-exposure treatment “very quickly”. It’s important to thoroughly wash the wound.
The ministry and Health New Zealand say rabies vaccination is recommended for New Zealanders travelling to countries where rabies is common – especially if you’re visiting rural areas, likely to be in contact with animals or if staying for longer than a month.
All travellers should avoid contact with animals in countries with rabies, especially dogs, it says.