18S rRNA Gene Of Babesia Research Articles

High prevalence of Babesia microti in small mammals in Beijing

BackgroundBabesiosis is an emerging tick-borne zoonotic infectious disease. Babesia microti is responsible for most cases of human babesiosis globally. It is important to investigate the prevalence of B. microti in the mammalian host population of a specific region in order to elucidate mechanisms of pathogen transmission and to define geographic areas where humans face the greatest risk of exposure. The aim of this study is to understand the prevalence and genotypes of B. microti in the small mammals that are found in Beijing, China.MethodsWe trapped small mammals from all of the 16 urban, suburban, and outer suburban districts of Beijing during the years 2014, 2017 and 2018. Genomic DNA was extracted from the heart tissues individually and the Babesia 18S rRNA gene was detected by PCR. The genotypes of B. microti were identified based on sequence alignments and phylogenetic analysis. The morphology of the parasites was observed under light microscopy. The risk factors were analyzed statistically based on both univariate analyses and multivariate logistic regression.ResultsA total of 1391 small mammals were collected. Positive infection of B. microti was detected in 12.1% (168/1391) of small mammals from 15 out of the 16 districts. Both Kobe-type and U.S.-type B. microti, accounting for 9.5% and 2.7%, respectively, were identified. Classic diverse morphologic forms of B. microti were observed. Specific types of ecological habitats including shrub areas, broad-leaved forest, and cropland were revealed to be risk factors associated with B. microti infection.ConclusionsThis study demonstrated the wide prevalence of B. microti infection in eight species of small mammals in Beijing, with Kobe-type more prevalent than U.S.-type. This study provides fundamental information for the development of informed prevention and control measures by public health authorities; the data gathered indicates a need for further monitoring of both clinical diseases in individuals presenting with babesiosis-like symptoms, as well as the infection status of ticks in high risk areas.

Detected microorganisms and new geographic records of Ornithodoros rietcorreai (Acari: Argasidae) from northern Brazil

Reliable data on distributional ranges of soft ticks (Argasidae) and assessments of putative tick-borne agents enhance the understanding on tick-associated microorganisms. A total of 96 ticks morphologicaly and molecularly identified as Ornithodoros rietcorreai were collected in Tocantins State, Brazil, using Noireau traps with living bait as CO2 source. Ninety-six ticks (54 nymphs, 32 males, 10 females) with different engorgement degrees were collected. Fourty-seven (48.9%) of them were individually screened by PCR for detecting bacteria of Anaplasmataceae family and genera Rickettsia, and Borrelia. The presence of protozoans of the genus Babesia was assessed as well. Fourty seven ticks were submitted to analysis. Nine ticks (19.1%) yielded sequences for gltA and htrA genes most identical with a series of endosymbiont rickettsiae and Rickettsia bellii, respectively. Upon two ticks (4.2%) we retrieved DNA of a potential new Wolbachia sp., and DNA of a putative novel Hepatozoon was characterized from three (6.4%) specimens. No DNA of Babesia or Borrelia was detected. Remarkably, amplicons of unidentified eukaryotic organisms, most closely related with apicomplexans but also with dinoflagellates (91% of identity after BLAST analyses), were recovered from two ticks (4.2%) using primers designed for Babesia 18S rRNA gene. Our records expand the distribution of O. rietcorreai into Brazilian Cerrado biome and introduce the occurrence of microorganisms in this tick species.

High-resolution melting PCR assay, applicable for diagnostics and screening studies, allowing detection and differentiation of several Babesia spp. infecting humans and animals

The goal of the study was to design a single tube PCR test for detection and differentiation of Babesia species in DNA samples obtained from diverse biological materials. A multiplex, single tube PCR test was designed for amplification of approximately 400 bp region of the Babesia 18S rRNA gene. Universal primers were designed to match DNA of multiple Babesia spp. and to have low levels of similarity to DNA sequences of other intracellular protozoa and Babesia hosts. The PCR products amplified from Babesia DNA isolated from human, dog, rodent, deer, and tick samples were subjected to high-resolution melting analysis for Babesia species identification. The designed test allowed detection and differentiation of four Babesia species, three zoonotic (B. microti, B. divergens, B. venatorum) and one that is generally not considered zoonotic—Babesia canis. Both detection and identification of all four species were possible based on the HRM curves of the PCR products in samples obtained from the following: humans, dogs, rodents, and ticks. No cross-reactivity with DNA of Babesia hosts or Plasmodium falciparum and Toxoplasma gondii was observed. The lack of cross-reactivity with P. falciparum DNA might allow using the assay in endemic malaria areas. The designed assay is the first PCR-based test for detection and differentiation of several Babesia spp. of medical and veterinary importance, in a single tube reaction. The results of the study show that the designed assay for Babesia detection and identification could be a practical and inexpensive tool for diagnostics and screening studies of diverse biological materials.

Infection with Babesia microti in humans with non-specific symptoms in North East Poland

Aim: The aim of the study was to evaluate the clinical course and effectiveness of diagnostics tools for Babesia spp. infection in patients bitten by ticks.Materials and methods: Five hundred and forty-eight patients hospitalised or seen in outpatients department because of various symptoms after a tick bite were included in the study. PCR, nucleotide sequencing of Babesia 18S rRNA gene fragment, blood smears and serological tests for Babesia spp., TBEV, A. phagocytophilum and B. burgdorferi were performed in all patients. Six patients infected with Babesia were included in the final analysis. They had PCR, Babesia 18S rRNA gene fragment nucleotide sequencing, blood smears and serological tests for Babesia spp., TBEV, A. phagocytophilum and B. burgdorferi performed twice.Results: Tick-borne infection with Babesia microti in six immunocompetent patients with non-specific symptoms was confirmed for the first time in Poland. No severe course of the disease was seen. No piroplasm forms were noticed within erythrocytes on blood smear. Three patients developed a serological response.Conclusions: Immunocompetent patients may be unaware of infection with Babesia microti after a tick bite. It must be included in the differential diagnosis after the tick bite. In patients with low parasitaemia PCR and serology seem useful when blood smear is negative. Self-elimination of Babesia spp. is possible, especially in cases with low parasitaemia.

BabesiaDNA Detection in Canine Blood andDermacentor reticulatusTicks in Southwestern Siberia, Russia

Babesia infection was studied in 21 blood samples of dogs with symptoms of babesiosis and among 72 Dermacentor reticulatus and 70 Ixodes persulcatus ticks from southwestern Siberia, Russia. Babesia DNA was detected by hemi-nested PCR based on the 18S rRNA gene with subsequent direct sequencing. All of the analyzed canine blood samples and three D. reticulatus, but none from I. persulcatus ticks studied were shown to contain Babesia DNA. Nucleotide sequences of the Babesia 18S rRNA gene fragment of 354 bp long for all 24 positive samples appeared to belong to the subspecies Babesia canis canis and differed only at three positions. The Babesia nucleotide sequences from 17 canine blood samples and from one D. reticulatus tick were identical to each other and to previously known B. canis canis from canine blood in Slovenia. Four canine blood samples and the second tick sample contained a mixture of two nucleotide sequences previously found in canine blood. B. canis canis nucleotide sequence from the third tick differed in the unique nucleotide transition and could correspond to a new genetic variant. Thus, the main etiological agent of canine babesiosis in Novosibirsk region is B. canis canis, and D. reticulatus, but not I. persulcatus, ticks could serve as a vector of this infectious agent. To our knowledge, this is the first report of the B. canis canis nucleotide sequences from ticks.