Journal article icon

Journal article

Plasmodium pitheci malaria in Bornean orang-utans at a rehabilitation centre in West Kalimantan, Indonesia

Abstract:
Background
Plasmodial species naturally infecting orang-utans, Plasmodium pitheci and Plasmodium silvaticum, have been rarely described and reportedly cause relatively benign infections. Orang-utans at Rescue Rehabilitation Centres (RRC) across the orang-utan natural range suffer from malaria illness. However, the species involved and clinical pathology of this illness have not been described in a systematic manner. The objective of the present study was to identify the Plasmodium species infecting orang-utans under our care, define the frequency and character of malaria illness among the infected, and establish criteria for successful diagnosis and treatment.

Methods
During the period 2017–2021, prospective active surveillance of malaria among 131 orang-utans resident in a forested RRC in West Kalimantan (Indonesia) was conducted. A total of 1783 blood samples were analysed by microscopy and 219 by nucleic acid based (PCR) diagnostic testing. Medical records of inpatient orang-utans at the centre from 2010 to 2016 were also retrospectively analysed for instances of symptomatic malaria.

Results
Active surveillance revealed 89 of 131 orang-utans were positive for malaria at least once between 2017 and 2021 (period prevalence = 68%). During that period, 14 cases (affecting 13 orang-utans) developed clinical malaria (0.027 attacks/orang-utan-year). Three other cases were found to have occurred from 2010–2016. Sick individuals presented predominantly with fever, anaemia, thrombocytopenia, and leukopenia. All had parasitaemias in excess of 4000/μL and as high as 105,000/μL, with severity of illness correlating with parasitaemia. Illness and parasitaemia quickly resolved following administration of artemisinin-combined therapies. High levels of parasitaemia also sometimes occurred in asymptomatic cases, in which case, parasitaemia cleared spontaneously.

Conclusions
This study demonstrated that P. pitheci very often infected orang-utans at this RRC. In about 14% of infected orang-utans, malaria illness occurred and ranged from moderate to severe in nature. The successful clinical management of acute pitheci malaria is described. Concerns are raised about this infection potentially posing a threat to this endangered species in the wild.
Publication status:
Published
Peer review status:
Peer reviewed

Actions

Access Document

Publisher copy:
10.1186/s12936-022-04290-8

Authors

More by this author
Role:
Author
ORCID:
0000-0003-4811-0332


More from this funder
Funder identifier:
https://ror.org/029chgv08
Programme:
Africa-Asia Programme Vietnam


Publisher:
BioMed Central
Journal:
Malaria Journal More from this journal
Volume:
21
Issue:
1
Article number:
280
Place of publication:
England
Publication date:
2022-10-03
Acceptance date:
2022-08-18
DOI:
EISSN:
1475-2875
Pmid:
36184593


Terms of use


Views and Downloads






If you are the owner of this record, you can report an update to it here: Report update to this record

TO TOP