Characterization of trypanosome isolates from naturally infected horses on a farm in Kenya.

This research investigates and characterizes specific types of parasitic unicellular organisms (trypanosome) that were found in Kenyan horses during a disease outbreak. The results revealed these organisms belonged to a sub-genus known as ‘Nannomonas’. They were further classified as ‘savannah’ type of a species known as Trypanosoma congolense, but with noticeable diversity within the isolates.

Research Methodology

• The researchers conducted this study following a disease outbreak in Kenyan horses over a period of 18 months. They collected about 18 trypanosome isolates from the infected animals for characterization.
• The isolates were cryopreserved; a process of preserving cells at very low temperatures, to allow for their future characterization.
• To categorize these isolates, the researchers used morphology (study of the physical shape and size of organisms) with Giemsa-stained blood and buffy coat smears. This is a popular method to visually distinguish and identify different trypanosome species.
• Animals’ susceptibility to infections also provides insights on the organism; hence, the team examined the infectivity of the isolates to mice.
• To further classify the organisms, the researchers used recombinant DNA hybridization, a process that identifies species based on their DNA composition.
• Orthogonal field alternation gel electrophoresis (OFAGE), a technique that separates chromosomes, was also used to distinguish the isolates based on their genetic profile.

Findings of the Study

• All the trypanosome isolates examined were identified as belonging to the subgenus Nannomonas of the Trypanosoma genus morphologically. This distinction was made based on the visible characteristics of the organisms after employing Giemsa-stained blood and buffy coat smears.
• Recombinant DNA hybridization allowed the researchers to further identify the isolates as the ‘savannah’ type of Trypanosoma congolense, another species of the Trypanosoma genus.
• Chromosome separation conducted on six clones derived from the isolates, displayed a profile characteristic of T. congolense, ‘savannah’ type. This finding was made using OFAGE, which allowed the scientists to identify the genetic composition of the isolates.
• The researchers observed that the medium-sized and minichromosomes in different isolates varied in number and positions. This was an indication of the diversity within the isolates, suggesting the presence of different strains or serodemes of T. congolense, ‘savannah’ type.

In conclusion, the disease outbreak in Kenyan horses was caused by several strains of the ‘savannah’ type of Trypanosoma congolense, a species under the Nannomonas sub-genus. This research provides valuable insights into the biological and genetic characterization of trypanosomes, which is crucial in understanding the disease dynamics and devising effective control strategies.