The epidemiology of melioidosis in the Balimo region of Papua New Guinea

Abstract

The distribution of Burkholderia pseudomallei was determined in soil collected from a rural district in Papua New Guinea (PNG) where melioidosis had recently been described, predominately affecting children. In 274 samples, 2.6% tested culture-positive for B. pseudomallei. Pulsed-field gel electrophoresis using SpeI digests and rapid polymorphic DNA PCR with five primers demonstrated a single clone amongst clinical isolates and isolates cultured from the environment that was commonly used by children from whom the clinical isolates were derived. We concluded that individuals in this region most probably acquired the organism through close contact with the environment at these sites. Burkholderia thailandensis, a closely related Burkholderia sp. was isolated from 5.5% of samples tested, an observation similar to that of melioidosis-endemic areas in Thailand. This is the first report of an environmental reservoir for melioidosis in PNG and confirms the Balimo district in PNG as melioidosis endemic.

Fig. 1

The villages of the Gogodala region are located predominately throughout the Aramia river floodplain which is about 30 km from the Fly River. The Aramia River feeds lagoon systems which seasonally flood. Villages are often established on land which is surrounded by these lagoons. Balimo village is located across a lagoon system 6 km to the northwest of Kimama. Adiba village is located on a separate lagoon system 11 km upriver from Balimo.

Fig. 2

SpeI digest PFGE patterns of three epidemiologically associated B. pseudomallei isolate groups.

Fig. 3

SpeI digest PFGE patterns demonstrating all clinically derived B. pseudomallei (C prefix) with the same genotype as epidemiologically unrelated clinical and environmental isolates shown in Figure 2. Included in rows 11–15 are PNG B. thailandensis genotype 1. Isolate A37 (row 1) is an uncharacterized environmental organism demonstrating considerable divergence from the other Burkholderia.

Fig. 4

SpeI digest patterns of PNG B. thailandensis genotypes II–X.