Differential diagnosis for malaria and trypanosomes in areas where the diseases co-exist
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Date
2021-01-13
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Kamuzu University of Health Sciences
Abstract
Type of study: This is a cross-section study to investigate the co-infection of trypanosome and malaria parasites in
areas where trypanosomiasis is endemic in Malawi.
Problem: Malaria is ubiquitous, treatment of Human African Trypanosomiasis (HAT) tends to be delayed as
the first diagnostic measure for any patient presenting with these symptoms gets malaria treatment
first (Darby et al., 2008). Malaria in Malawi is mainly caused by Plasmodium falciparum and
diagnosis requires a Malaria Rapid Diagnostic Test (mRDT) at the point of care which is an
antibody/antigen test and microscopy of stained blood films is sometimes used. There are two
main mRDT in use in Malawi, one developed based on Plasmodium histidine-rich protein (HRP)
2 (pHRP-2) antigen and the other based on Plasmodium lactate dehydrogenase (LDH) (pLDH)
antigen both of which mainly target P. falciparum. HAT in Malawi is caused by T.brucei
rhodesiense and standard of care diagnosis requires microscopy of stained blood smears
although not sensitive when parasitemia is low (Manful et al., 2010). Published reports have
revealed that Trypanosome parasite hide underneath the skin of some individuals although there
may be no circulating parasites in the blood as one way of invading host adaptive immunity. The
parasites may reside underneath the skin for years without being detected in blood circulation. This
complicates the diagnosis of HAT as such individuals are diagnosed as microscopically negative
for HAT disease and often sent home on antimalaria treatment without further diagnosis.
Main objective: To investigate differential diagnosis of Malaria and Trypanosomiasis in Rumphi and Nkhokakota
Specific Objectives:
1. To assess the magnitude of HAT patients that are missed out when using microscopy for
diagnosis in comparison with a diagnostic HAT PCR.
2. To identify individuals co-infected with Malaria and Trypanosomes
3. To determine whether HAT positive individuals detected are infected with cutaneous
trypanosomes.
4. To Identify differences in T.b. rhodesiense parasite gene expression when isolated in skin and
or blood.
Methodology: Patients that were pre-screened by medical personnel at the hospital for febrile symptoms and sent
for Malaria test at the laboratory will be recruited for a period of two weeks to meet our sample
size of 123 participants for both Nkhotakota and Rumphi district hospitals. Venous blood specimen
will be collected from each participant for further laboratory analysis. Firstly, the blood will be parasites will be sent for treatment immediately following standard treatment guidelines for each
disease used to screen for Malaria parasites using Malaria Rapid Diagnostic (RDT) test. Microscopy will
be used to confirm individuals who are Malaria RDT positive. Lastly, the other part of the blood
will be used for microscopic examination for diagnosis of HAT disease at the district hospital
Blood samples that are microscopic negative for HAT will further be tested using a diagnostic HAT
PCR at the College of Medicine to rule out any HAT cases that might be missed by the low
sensitivity microscopic examination. Individuals that are HAT positive by either microscopy or
PCR will be requested to have a small skin snip for further laboratory examination to identify
cutaneous Trypanosomes. All participants who are positive for either Malaria or Trypanosome
Expected Findings/Dissemination Study
This study is expecting to identify the HAT cases that are missed during diagnosis in the two
HAT endemic district hospitals of Malawi. The study will also help identify factors that influence
mis-diagnosis of HAT in endemic areas of Malawi. Findings from this study will be disseminated
at COMREC, College of Medicine Neglected Tropical Disease Research group, Trypanogen
Project, Peer reviewed journals and research conferences.
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Research Subject Categories::MEDICINE