Comparison of molecular techniques for the detection of Toxoplasma gondii in raw bovine milk from small rural properties in Brazil

This study aimed to research Toxoplasma gondii DNA in 102 samples of raw bovine milk from expansion tanks, in small properties located in different cities of the Midwest region of São Paulo, Brazil. For this, polymerase chain reaction (PCR) was performed with the primers TOX4/TOX5 for cPCR (conventional PCR), TgNP1/TgNP2 gene for nested PCR and the Tg18s58F/Tg18s348R for nested PCR. It was possible to detect T. gondii DNA in 18 (17.65 %) milk samples from the 102 tanks, corresponding to 4.90 % for TOX4/TOX5 primers, 12.74 % for TgNP1/TgNP2 gene and 0.98 % for Tg18s58F/Tg18s348R gene. The results showed that the TgNP1 and TgNP2 genes were more efficient to detect T. gondii DNA, and also indicated the importance of raw bovine milk as a source of human infections caused by this protozoan, being a public health problem. It is important to continue studies involving T. gondii from bovine milk considering the need for proper pasteurization, and for better comprehension regarding the epidemiology of this protozoan.

Detection of Leishmania spp. in Cats: Analysis of Nasal, Oral and Conjunctival Swabs by PCR and HRM

BACKGROUND AND OBJECTIVES

Feline leishmaniasis (FeL) is caused by several species of parasites of the genus Leishmania. The disease can occur with the presence or absence of clinical signs, similar to those observed in other common infectious diseases. In endemic regions for FeL, the infection has been associated with dermatological lesions. Therefore, considering the search for less invasive and more effective diagnostic techniques, we aimed to investigate the presence of Leishmania spp. in domestic cats through Polymerase Chain Reaction (PCR) and high-resolution melting (HRM) analyses of conjunctival, oral, and nasal epithelial cells, and we detected the presence of anti-Leishmania IgG antibodies from serological techniques of the Immunofluorescent Antibody Test (IFAT) and ELISA.

METHODS

The PCR and HRM for detection of Leishmania spp. were performed on 36 samples of epithelial cells from the conjunctiva of male and female cats, collected using sterile swabs. The serological tests IFAT and ELISA were also performed.

RESULTS

The prevalence of Leishmania donovani infection was 11.1% (4/36) by PCR assay, and those results were confirmed for Leishmania species using the HRM technique. Twenty-four cats (24/36 = 66.7%) were reactive to the IFAT and twenty-two cats were reactive by the ELISA technique (22/36 = 61.1%).

INTERPRETATION AND CONCLUSIONS

The use of conjunctival swabs was shown to be a non-invasive, practical, and easy-to-perform technique, and in addition to the genetic sequencing and HRM, it was able to identify the parasitic DNA of L. donovani in cats. This technique can be used for screening diagnosis in future epidemiological surveys of FeL and can be used as a complement to clinical and/or serological tests, as well as associating the clinical history of the animal, for the diagnostic conclusion.

Frequency, spatial distribution, and genetic diversity of Blastocystis among referred individuals to a clinical laboratory: First report of subtype 9 in Brazil

The enteric protist Blastocystis has a worldwide distribution, however its prevalence in the human population is still underestimated, especially in developing countries where proper diagnosis is not performed in the routine of clinical laboratories. In this study, we aimed to assess the frequency, genetic diversity, and spatial distribution of Blastocystis isolates detected in fecal samples referred to a clinical laboratory for routine examination in inner São Paulo State, Brazil. A total of 348 leftover stool samples available for disposal from female and male individuals with age ranging from 3 months to 88 years were analyzed by both microscopic examination and PCR/sequencing of the SSU rRNA gene. The overall frequency of Blastocystis sp. was 31% (108/348), including 20.1% (70/348) and 31% (108/348) by microscopic examination and PCR/sequencing, respectively. Significant association was found only between Blastocystis infection and age, since the highest rate of positive samples was detected among 5-9 years old individuals (p < 0.0001). In addition, spatial distribution revealed a wide distribution of the positive samples, however they were densely concentrated in more populated areas. Seven subtypes were identified, namely ST1 (40.7%), ST2 (9.2%), ST3 (45.3%), ST4 (0.9%), ST6 (1.8%), ST7 (0.9%) and ST9 (0.9%). The intra-subtype analysis revealed a total of 25 different alleles previously reported. Here, the findings lead us to highlight the following aspects: (1) the identification of a ST9 isolate is a relevant finding since it is considered a very rare subtype in human infections as well as this is the first report in Brazil; (2) the high frequency of Blastocystis in fecal samples submitted for examination in a clinical laboratory points to the need to consider its search in routine parasitological examinations, (3) the spatial distribution of Blastocystis infection was not homogeneous but concentrated in more populated areas where the access for population to diagnostic services in healthcare is likely to be easier and, (4) the genetic variability of Blastocystis isolates suggests exposure of inhabitants living in inner municipalities to different sources of contamination involving anthroponotic and zoonotic transmission pathways.

Commercially acquired açaí pulps contamination by Trypanosoma cruzi

The etiological agent of Chagas disease is the protozoan Trypanosoma cruzi. According to the World Health Organization, about seven to eight million people are infected with T. cruzi worldwide. The main routes of transmission are vectorial and oral, which has assumed great epidemiological importance, since there is no legislation that requires the pasteurization of açaí pulp. The present work aimed to look T. cruzi in 35 samples of açaí ice cream sold at different points of sale, covering 11 different cities in São Paulo State. Thus, the parasitological technique of forced sieving and the molecular test of Polymerase Chain Reaction were performed. For PCR analysis were used the 121/122 primer that amplifies the kinetoplast of the T. cruzi DNA (kDNA). By the forced sieving technique, the açaí pulp aliquots were analyzed under different storage temperatures and in different periods. One positive sample (2.86%) were observed at six hours at room temperature, but without motility and negative to the PCR technique. Two other açaí samples (5.71%) were positive by PCR, but negative by forced sieving. The results indicate the need for quality control and good manufacturing practices for the safe consumption of açaí-derived products.