Open AccessThe use of molecular technology to investigate trypanosome infections in tsetse flies at Liwonde Wild Life Reserve
Author(s) -
Symon Fidelis Nayupe,
Nelson V. Simwela,
Peace M. Kamanga,
John Chisi,
Edward Senga,
Janelisa Musaya,
Emmanuel Maganga
Publication year - 2020
Publication title -
malawi medical journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 18
eISSN - 1995-7270
pISSN - 1995-7262
DOI - 10.4314/mmj.v31i4.3
Subject(s) - trypanosoma brucei , loop mediated isothermal amplification , tsetse fly , african trypanosomiasis , trypanosomiasis , biology , polymerase chain reaction , trypanosoma brucei rhodesiense , trypanosoma , parasite hosting , veterinary medicine , virology , medicine , dna , ecology , genetics , gene , world wide web , computer science
BackgroundTrypanosomes are protozoan flagellates that cause human African trypanosomiasis (HAT) and African animal trypanosomiasis (AAT). HAT is caused by Trypanosoma brucei rhodesiense in East and Central Africa and T.b. gambiense in West Africa, whereas AAT is caused by a number of trypanosome species, including T. brucei brucei, T. evansi, T. vivax, T. congolense, T. godfreyi and T. simiae. The aim of this study was to establish if tsetse flies at Liwonde Wild Life Reserve (LWLR) are infected with these trypanosomes and thus pose a risk to both humans and animals within and surrounding the LWLR. MethodsA total of 150 tsetse flies were caught. Of these, 82 remained alive after capture and were dissected such that the mid-gut could be examined microscopically for trypanosomes. DNA extractions were performed from both mid-guts and the 68 dead flies using a Qiagen Kit. Amplification techniques involved the Internal Transcriber Spacer 1 (ITS 1) conventional polymerase chain reaction (PCR) with primers designed to identify trypanosome species, and Repetitive Insertion Mobile Element – Loop Mediated Isothermal Amplification (RIME LAMP), a sequence specific to T. brucei.ResultsAnalysis showed that 79/82 (96.3%) of the mid-guts examined microscopically were positive for trypanosomes and that 75/150 (50%) of the DNA extracts (from the mid-gut, and tsetse fly carcasses) were positive for T. brucei, as determined by the RIME LAMP method. ITS1 PCR further showed that 87/150 (58.0%) flies were positive for trypanosomes, of which 56/87 (64.4%) were T. brucei, 9/87 (10.3%) were T. vivax; 7/87 (8.1%) were T. simiae; 6/87 (6.9%) were T. congolense, and 6/87 (6.9%) were T. godfreyi. Ten samples had a mixture of infections. ConclusionOur analysis demonstrated a mixture of infections from trypanosome species in tsetse flies at LWLR, and that T. brucei, the species that causes HAT, was the most common. Our study successfully used molecular techniques to demonstrate the presence of T. b. rhodesiense at LWLR, a species that causes HAT in both East and Central Africa.