26 Jan 2021
Understanding the dramatic rise of typhoid fever in Fiji
A Typhoid Taskforce hunts for research clues about why Fiji has become a hot spot for typhoid and whether a vaccine could eradicate the problem.
Typhoid fever has been endemic in Fiji for many decades, but the incidence increased in the mid 2000s.
This bacterial infection is caused by Salmonella enterica serovar Typhi, which can be transmitted either directly among humans or from infected humans to the environment and then back into humans.
“In the middle of the 2000s there was a big uptick in case numbers,” says University of Melbourne Professor Dick Strugnell.
“It wasn’t clear whether the incidence went up because the surveillance was better or because it was more infectious.”
Professor Strugnell is part of a research taskforce working with the Murdoch Children’s Research Institute and the Fiji Ministry of Health and Medical Services that’s trying to work out why case numbers have risen so dramatically.
“The disease has a very strange epidemiology. If you test Fijians blind to their ethnicity, the serological footprint of disease is the same,” explains Professor Strugnell.
“However, when you look at the clinical records, it’s only the iTaukei Fijians who are presenting with the disease. There’s an anomaly we don’t understand.”
Through the collection of isolates, University of Melbourne researcher, Dr Mark Davies, has conducted genomic analysis of the bacteria collected by the Typhoid Taskforce and found two major strains.
“We’ve now got quite a complex picture of how the disease is being transmitted and we’re not seeing much antibiotic resistance, which is the good thing,” says Professor Strugnell.
“There’s a global strain circulating that’s becoming increasingly resistant to commonly used antibiotics.”
Most recently, the focus of the Taskforce has been on understanding local transmission, the role of the environment in transmission and hot spots of disease.
This work is being conducted by University of Melbourne PhD candidate, Dr Aneley Getahun, in collaboration with staff of the Fiji Ministry of Health and Medical Services. Dr Getahun is a public health physician.
One of her roles is to visit the households of typhoid patients identified in hospitals to understand the risk factors associated with the disease. “We see a lot of people who live with very limited resources where there is overcrowding and poor sanitation,” says Dr Getahun.
Professor Strugnell says the biggest opportunity to reduce numbers of typhoid cases in Fiji is to implement a new vaccine.
“The Typhoid Taskforce is working with the International Vaccine Institute in Seoul to implement a new vaccine approved by the World Health Organization, called the typhoid conjugate vaccine. Ideally, we’ll endeavour to vaccinate everyone on Vanua Levu and then study the impact on the disease as a means of trying to eradicate it.”
This article was first published in the Celebrating Five Years of the Doherty Institute Impact Report.