Transmissibility, by Glossina morsitans morsitans, of Trypanosoma congolense strains during the acute and chronic phases of infection

• Published in: Acta tropica Vol. 113; no. 2; pp. 195 - 198
• Main Authors: Masumu, J., Akoda, K., Van den Bossche, P.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 01.02.2010; Elsevier
• Subjects: Acute Disease; Acute phase; Animals; Biological and medical sciences; Chronic Disease; Chronic phase; General aspects; Glossina morsitans morsitans; Host-Parasite Interactions; Insect Vectors - parasitology; Male; Medical sciences; Mice; Transmissibility; Trypanosoma; Trypanosoma congolense; Trypanosoma congolense - classification; Trypanosoma congolense - physiology; Trypanosomiasis, African - parasitology; Trypanosomiasis, African - transmission; Tsetse Flies - parasitology; Transmissibility; Acute phase; Chronic phase; Trypanosoma congolense; Glossina morsitans morsitans; Kinetoplastida; Protozoa; Chronic; Acute; Tropical medicine
• ISSN: 0001-706X; 1873-6254
• DOI: 10.1016/j.actatropica.2009.09.002

In order to verify whether chronic trypanosomal infections can affect the transmissibility of Trypanosoma congolense by tsetse flies, batches of Glossina morsitans morsitans were fed on mice infected with the same level of parasitemia (10 8.1 trypanosomes/ml of blood) of two cloned low virulent T. congolense strains during the acute and the chronic phases of infection. Results showed that the proportions of procyclic infections in flies that were fed during the acute phase (32.6% and 45.4% for isolates 1 and 2, respectively) were significantly higher ( χ 2 = 4.7, P < 0.05 and χ 2 = 23.7, P < 0.0001, respectively) compared to the proportions of procyclic infections of flies fed during the chronic phase of infection (18.8% and 14.9% for isolates 1 and 2, respectively). Similarly the proportions of metacyclic infections in flies fed during the acute phase (32.6% and 45.4% for isolates 1 and 2, respectively) were significantly higher ( χ 2 = 6.3, P < 0.05 and χ 2 = 23.7, P < 0.0001, respectively) compared to the proportions of metacyclic infections in flies fed during the chronic phase of infection (16.8% and 14.9% for isolates 1 and 2, respectively). No significant difference was found in the maturation rate of both strains during the acute phase compared to the chronic phase of infection ( P > 0.05). The results of this study suggest that T. congolense loses part of its transmissiblity by tsetse flies during the chronic phase of infection.