An outbreak of Plasmodium vivax malaria in Far North Queensland, 2002

Abstract

Objective: To describe an outbreak of Plasmodium vivax malaria in Far North Queensland in 2002. Design: Epidemiological and entomological investigations; molecular analyses of the infecting parasites. Main outcome measures: Case characteristics, adult and larval mosquito counts at the outbreak location, haplotyping of parasites in blood samples from different cases determined through sequencing of AMA1 and MSP1 genes. Results: A man with imported P. vivax malaria stayed at a camping ground 95 km north of Cairns in late September 2002. This led to an outbreak of P. vivax malaria in 10 adults who stayed at the camping ground in October. Large numbers of Anopheles farauti sensu lato larvae were present in stagnant pools in a creek at the camping ground, and many adult mosquitoes were collected nearby. Not only had most of the infected patients been exposed to mosquitoes at night, they were also less likely than other campers to have used insect repellents appropriately (odds ratio, 0.01; P < 0.001). Two different haplotypes of P. vivax, only one of which was detected in the imported case, were involved in the outbreak. Conclusions: Although local transmission of malaria is rare in Far North Queensland, the risk is probably higher in the dry season (September to December). Campers need to be aware of the increased risk of mosquito‐borne diseases. Sexual recombination of multiple gametocytes in mosquitoes infected by the imported case may have resulted in the two haplotypes of P. vivax involved in the outbreak.

Dengue fever: is it endemic in Australia?

“…The north Queensland coast was considered endemic for malaria with a large epidemic in 1942 leading to the establishment of a malaria research unit in Cairns under the guidance of Colonel Neil Hamilton Fairley. The combination of effective malaria control in the allied forces combined with civilian mosquito control measures led to the disappearance of malaria soon after World War II, although sporadic epidemics, linked to introduced cases, have occurred since 2,3 …”

Notifications of imported malaria in Western Australia, 1990–2001: incidence, associated factors and chemoprophylaxis

“…Most cases are caused by Plasmodium vivax , but a third are caused by the potentially more serious Plasmodium falciparum 3 , 4 . There is an expanding malaria‐receptive zone in northern Australia, with Anopheles farauti the vector, 5 and several outbreaks of vivax malaria have occurred in northern Queensland following importation, the latest in 2002 6 . Drug‐resistant Plasmodium strains are found increasingly in tropical countries, 7 and their introduction into northern Australia could have serious consequences.…”

Molecular and epidemiological characterization of Plasmodium vivax recurrent infections in southern Mexico

“…Several studies have employed genetic markers to facilitate identification of P. vivax relapse infections [17,26,30,39,40], and WHO has recommended the use of at least one polymorphic marker to aid distinction between homologous and heterologous infections [10]. In this study, we used two types of polymorphic markers, PCR-RFLP size polymorphism in cspr and msp3a and a set of seven microsatellites, to develop criteria for identifying putative relapse infections in southern Mexico.…”