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First detection and molecular identification of Entamoeba bovis from Japanese cattle

Matsubayashi M, Matsuura Y, Nukata S, Daizi Y, Shibahara T, Teramoto I, et al.

Parasitol Res, 2018 Jan;117(1):339-342.
PMID: 29185030 DOI: 10.1007/s00436-017-5689-2

Thus far, Entamoeba species have been classified based on morphology such as the number of nuclei in mature cysts and their hosts. Using recently developed molecular tools, ruminant Entamoeba spp. are currently classified into four species/genotypes: E. bovis and Entamoeba ribosomal lineages (RL) 1, 2, and 4. However, the distribution or pathogenicity of ruminant Entamoeba has not been well documented. In the present study, we examined a total of 25 fecal and seven environmental samples collected from six farms in Japan from 2016 to 2017 by the floatation method and PCR and sequencing analyses. Consequently, we detected Entamoeba cysts in 18 of 25 cattle samples and four of the seven environmental samples, including soil and drinking water, by microscopic examinations. In sequential examinations, Entamoeba-positive cattle were found to shed cysts without any clinical symptoms for more than 8 months. By PCR for molecular identification, isolates in ten cattle and one soil sample were successfully sequenced and formed a cluster of E. bovis, which was separated from those of other Entamoeba species/genotypes such as RL1-4 in phylogenetic analysis. To our knowledge, this is the first report about E. bovis in Japan, and our results may implicate that E. bovis is not pathogenic.
Fulltext Improvement of malaria diagnostic system based on acridine orange staining

Kimura M, Teramoto I, Chan CW, Idris ZM, Kongere J, Kagaya W, et al.

Malar J, 2018 Feb 07;17(1):72.
PMID: 29415724 DOI: 10.1186/s12936-018-2214-8

BACKGROUND: Rapid diagnosis of malaria using acridine orange (AO) staining and a light microscope with a halogen lamp and interference filter was deployed in some malaria-endemic countries. However, it has not been widely adopted because: (1) the lamp was weak as an excitation light and the set-up did not work well under unstable power supply; and, (2) the staining of samples was frequently inconsistent.
METHODS: The halogen lamp was replaced by a low-cost, blue light-emitting diode (LED) lamp. Using a reformulated AO solution, the staining protocol was revised to make use of a concentration gradient instead of uniform staining. To evaluate this new AO diagnostic system, a pilot field study was conducted in the Lake Victoria basin in Kenya.
RESULTS: Without staining failure, malaria infection status of about 100 samples was determined on-site per one microscopist per day, using the improved AO diagnostic system. The improved AO diagnosis had both higher overall sensitivity (46.1 vs 38.9%: p = 0.08) and specificity (99.0 vs 96.3%) than the Giemsa method (N = 1018), using PCR diagnosis as the standard.
CONCLUSIONS: Consistent AO staining of thin blood films and rapid evaluation of malaria parasitaemia with the revised protocol produced superior results relative to the Giemsa method. This AO diagnostic system can be set up easily at low cost using an ordinary light microscope. It may supplement rapid diagnostic tests currently used in clinical settings in malaria-endemic countries, and may be considered as an inexpensive tool for case surveillance in malaria-eliminating countries.
Evaluation of the detection method by a flotation method using a wire loop for gastrointestinal parasites

Takano A, Morinaga D, Teramoto I, Hatabu T, Kido Y, Kaneko A, et al.

Vet Med Sci, 2024 Sep;10(5):e70007.
PMID: 39207196 DOI: 10.1002/vms3.70007

Infections by gastrointestinal parasites are found in a variety of animals worldwide. For the diagnosis of such infections, the flotation method is commonly used to detect parasitic microorganisms, such as oocysts or eggs, in feces. Instead of adding a flotation solution after the final centrifugation step and using a cover slip to collect the parasites, the method using a wire loop for the recovery of the organisms has been reported as one of alternative methods. However, the recovery rates of microorganisms from the flotation method have not been analysed. In the present study, the utility of a flotation method with the use of a wire loop of 8 mm in diameter (the loop method) was evaluated using different numbers of E. tenella oocysts and Heterakis gallinarum eggs, and chicken fecal samples collected at the farms. Consequently, we found that the oocysts and eggs in tubes could be collected at a ratio of 2.00 to 3.08. Thus, our results indicate that the loop method is a simple and time saving method, implicating the application for the estimated OPG/ EPG (Oocysts/Eggs per gram) of the samples.
Fulltext High and Heterogeneous Prevalence of Asymptomatic and Sub-microscopic Malaria Infections on Islands in Lake Victoria, Kenya

Idris ZM, Chan CW, Kongere J, Gitaka J, Logedi J, Omar A, et al.

Sci Rep, 2016 11 14;6:36958.
PMID: 27841361 DOI: 10.1038/srep36958

Kenya is intensifying its national efforts in malaria control to achieve malaria elimination. Detailed characterization of malaria infection among populations living in the areas where the disease is endemic in Kenya is a crucial priority, especially for planning and evaluating future malaria elimination strategy. This study aimed to investigate the distribution and extent of malaria infection on islands in Lake Victoria of Kenya to aid in designing new interventions for malaria elimination. Five cross-sectional surveys were conducted between January 2012 and August 2014 on four islands (Mfangano, Takawiri, Kibuogi and Ngodhe) in Lake Victoria and a coastal mainland (Ungoye). Malaria prevalence varied significantly among settings: highest in Ungoye, followed by the large island of Mfangano and lowest in the three remaining small islands. Of the 3867 malaria infections detected by PCR, 91.8% were asymptomatic, 50.3% were sub-microscopic, of which 94% were also asymptomatic. We observed geographical differences and age dependency in both proportion of sub-microscopic infections and asymptomatic parasite carriage. Our findings highlighted the local heterogeneity in malaria prevalence on islands and a coastal area in Lake Victoria, and provided support for the inclusion of mass drug administration as a component of the intervention package to eliminate malaria on islands.