Epidemiology of malaria in the Papua New Guinean highlands
Objectives To conduct an in‐depth investigation of the epidemiology of malaria in the Papua New Guinea (PNG) highlands and provide a basis for evidence‐based planning and monitoring of intensified malaria control activities.
Methods Between December 2000 and July 2005, 153 household‐based, rapid malaria population surveys were conducted in 112 villages throughout the central PNG highlands. The presence of malaria infections was determined by light microscopy and risk factors assessed using a structured questionnaire. The combined dataset from all individually published surveys was reanalysed.
Results The prevalence of malaria infections in the different surveys ranged from 0.0% to 41.8% (median 4.3%) in non‐epidemic surveys and 6.6% to 63.2% (median 21.2%, P < 0.001) during epidemics. Plasmodium falciparum was the predominant infection below 1400 m and during epidemics, Plasmodium vivax at altitudes >1600 m. Outside epidemics, prevalence decreased significantly with altitude, was reduced in people using bed nets [odds ratio (OR) = 0.8, P < 0.001] but increased in those sleeping in garden houses (OR = 1.34, P < 0.001) and travelling to highly endemic lowlands (OR = 1.80, P < 0.001). Below 1400 m, malaria was a significant source of febrile illness. At higher altitudes, malaria was only a significant source of febrile illness during epidemic outbreaks, but asymptomatic malaria infections were common in non‐epidemic times.
Conclusions Malaria is once again endemic throughout the PNG highlands in areas below 1400–1500 m of altitude with a significant risk of seasonal malaria outbreaks in most area between 1400–1650 m. Ongoing control efforts are likely to result in a substantial reduction in malaria transmission and may even result in local elimination of malaria in higher lying areas.
Document Type: Research Article
Affiliations: 1: PNG Institute of Medical Research, Goroka, Papua New Guinea 2: Malaria Surveillance and Control Unit, Goroka, Papua New Guinea 3: The Burnet Institute of Medical Research and Public Health, Prahan, Vic., Australia
Publication date: 2012-10-01