House mice are a critical yet underestimated source of the bacterial disease leptospirosis in New Zealand, which means anyone in contact with mice could be at risk of infection, not just farmers, according to a study released on Tuesday.
<img src='https://news.cgtn.com/news/2024-07-23/New-Zealand-study-shows-mice-silently-spread-leptospirosis-1vtnU3Hl0pa/img/bf95f094222a44419a9836dfac0da3b6/bf95f094222a44419a9836dfac0da3b6.jpeg' alt='A leptospira bacterium through a microscope. /VCG'
Leptospirosis is a disease caused by bacteria that affects people and animals. It is spread in the urine of infected animals.
The study, jointly conducted by New Zealand researchers from Massey University, ecologists from the University of Auckland, and Brazilian wildlife veterinarians, found that two-thirds of reported leptospirosis cases result in hospitalization, with half experiencing long-lasting symptoms.
Cases have usually been linked back to livestock, creating the misconception that it is a farmer’s disease. However, the team’s modeling data found the risk of getting leptospirosis from house mice remains significant regardless of how dense mouse populations are, with nine out of 10 mice found to be infected even when there are not many mice around.
The study, published in the Journal of Applied Ecology, aims to assess the density of infected mice within populations and understand their implications for disease transmission on a broader scale.
Lead researcher Marie Moinet said infected mice tend to roam more extensively, potentially spreading the disease further, calling for increased awareness of mice as a source of leptospirosis.
By integrating ecological and epidemiological methodologies, the research provides new insights into wildlife disease dynamics, with mice being underemphasized as disease carriers within New Zealand, Moinet said, adding that given the ubiquitous presence of mice across the country, their population sizes often go unnoticed until they reach outbreak levels.
“Contact with infected mammal urine or contaminated water poses a significant transmission risk, with house mice harboring the prominent Ballum strain in recent cases,” she said.
Professor Jackie Benschop of Massey University said the research highlights the need for greater attention to rodent control to safeguard public health.
“Pest control measures should not be limited to times of high density, and it’s likely climate change and our recent flooding incidents will aggravate the problem,” Benschop said.
