The infection of Cysticercus fasciolaris in natural rats (Rattus species) residing in human residence areas, Nakhon Si Thammarat, Thailand.

Cysticercus fasciolaris (C. fasciolaris) is the larval stage of a cestode parasite named Taenia taeniaeformis (T. taeniaeformis). C. fasiolaris is found in small rodents, especially rats. Rattus species are listed as intermediate hosts of this parasite, and cats are the main definitive host of C. fasiolaris. The objective of this study was to study the pathological, microscopic, and molecular aspects of C. fasciolaris in rodents residing in human residence areas. One hundred and two rodents were trapped in human settlements and dissected for larva-containing cyst examinations in the body cavity. The larvae of C. fasciolaris were investigated using histopathological examination, microscopic observations under a stereomicroscope and scanning electron microscope, and molecular detection using polymerase chain reaction. The prevalence of hepatic cysts containing larvae was 8.91% (95% CI = 4.16-16.24). In addition, the older larvae also had longer micropapillae. Histopathological investigation revealed normal hepatic tissue containing larvae and a scanty fluid cyst. The cyst capsule contains mostly mononuclear cells and spindle cells in all infected rats. The molecular detection using two primer sets revealed the amplicons were similar to the clade of C. fasciolaris. In the future, more investigation is necessary to fully understand the parasite's molecular pathogenesis and virulent molecules, which are less obvious.

Trypanosoma lewisi in blood of Rattus rattus complex residing in human settlements, Nakhon Si Thammarat, Thailand: Microscopic and molecular investigations.

Trypanosomes are blood parasites infected in various mammals, including rats. The presence of rats in human settlements can increase the chance of Trypanosoma transmission to humans. The molecular study of multispacer in Trypanosoma spp. in naturally infected rodents in Thailand is scanty. The objective of this study was to detect Trypanosoma in the blood of the captured rats in Nakhon Si Thammarat, Thailand, using microscopic and molecular techniques. This was a cross-sectional study conducted in human settlement areas. Ninety-nine blood samples were collected using cardiac puncture. A blood sample was smeared on a glass slide and examined using a compound light microscope and a scanning electron microscope. Moreover, polymerase chain reaction was applied to detect Trypanosoma evansi and T. lewisi in the blood. An additional primer set was used to confirm the species of the detected trypanosome. Approximately 18% of the rats had positive Trypanosoma infections. All Trypanosoma-positive blood samples were matched with sequences of T. lewisi. The stumpy form of trypanosome had higher nucleus related parameters than the slender form. Interestingly, the partial sequences of the alpha-tubulin gene of T. lewisi were first reported in the naturally infected RrC in this study. Based on the results obtained, T. lewisi biology, particularly the virulent components and route of transmission, pathogenesis, and in vitro experiments, are strongly recommended for further study.