Detection of Babesia bigemina DNA in ticks by DNA hybridization using a nonradioactive probe generated by arbitrary PCR

Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks

Transovarial transmission (TOT) is an efficient vertical transmission of pathogens that is observed in many arthropod vectors. This method seems to be an evolutionarily unique development observed only in Babesia sensu stricto (clade VI) and Rickettsia spp., whereas transstadial transmission is the common/default way of transmission. Transovarial transmission does not necessarily contribute to the amplification of tick-borne pathogens but does contribute to the maintenance of disease in the environment. This review aims to provide an updated summary of previous reports on TOT of tick-borne pathogens.

Molecular detection of pathogens in the ova and unfed larvae of Rhipicephalus annulatus and Haemaphysalis bispinosa ticks infesting domestic cattle of south India

This study aimed to investigate the presence of pathogens in the engorged ticks infesting domestic cattle, their ova, and unfed larvae. The engorged female ticks infesting domestic cattle of Wayanad district of Kerala, south India were collected and kept for oviposition. The dead females after the complete oviposition, their egg masses, and unfed larvae were screened for the presence of various pathogens by specific PCRs. The presence of Babesia bigemina, Anaplasma marginale, A. phagocytophilum, and Rickettsia spp. similar to R. raoultii was confirmed in Rhipicephalus annulatus ticks, their egg masses, and unfed larvae. Theileria orientalis was detected in Rh. annulatus females, but not in their egg masses or progenies. The presence of A. phagocytophilum and Rickettsia spp. similar to R. raoultii was confirmed in Haemaphysalis bispinosa ticks, their egg masses, and unfed larvae too. The presence of coinfections of B. bigemina with A. phagocytophilum and A. marginale were detected in Rh. annulatus ticks and their progenies.

Molecular prevalence of Babesia bigemina in Rhipicephalus microplus ticks infesting cross-bred cattle of Punjab, India

Babesiosis is an economically important tick-borne apicomplexan protozoan disease of cattle in tropical and subtropical regions. In the present study, Rhipicephalus microplus engorged female ticks were collected from 135 apparently healthy cattle from different agro-climatic zones of Punjab, India, to investigate the carrier status of Babesia bigemina infection in vector tick by using microscopy and PCR based assays. PCR when applied on DNA extracted from the egg masses harvested from ticks showed 1.48% (2/135) samples as positive, whereas 4.44% (6/135) samples were positive when product of primary PCR was used as template in nPCR. Further, among the DNA samples isolated from the unfed larval stages that emerged from egg masses laid by ticks, only 1.48% (2/135) samples were detected as positive for B. bigemina in PCR, while 7.41% (10/135) samples were detected positive in nPCR assay. Statistically, non-significant (p > 0.05) difference in prevalence rates was observed across different agro-climatic zones and between different age groups of cattle from which engorged ticks were collected. It can, thus, be concluded that prevalence of B. bigemina in the vector tick, R. microplus in Punjab state of India indicates an endemic status of the organism and a further study is needed for the management and control of the bovine babesiosis.

Morphology, epidemiology, and phylogeny of Babesia: An overview

Babesiosis is a tick-borne hemoprotozoan disease of domestic and wild animals. The disease is caused by various species of Babesia and some species of Babesia have also zoonotic significance. The parasite in vertebrate hosts’ remains in erythrocytes and the morphology of Babesia spp. is not uniform in all vertebrate hosts. With the advancement of science, particularly the use of molecular techniques made it easy to study the evolution of parasites and thereby reclassifying Babesia spp. as per their phylogeny and to establish the relation of one isolate of Babesia spp. with isolates throughout the world. An attempt also made in this communication to enlighten the readers regarding relationship of one isolate of Babesia spp. of a particular area to another isolate of Babesia spp. of that area or other parts of the world and phylogenetic classification of Babesia spp. was also discussed. It has been concluded that as the study on Babesia is complex in nature so monitoring of the infection with the use of modern techniques is very much needed to control the infection. Second, more research work on phylogenetic relationship of Babesia spp. isolated from different hosts is needed, particularly in India to know the evolution of Babesia spp. of a particular area, as it has great importance to study the trans boundary diseases of animals.

Molecular identification of Theileria and Babesia in ticks collected from sheep and goats in the Black Sea region of Turkey

A molecular survey was undertaken in the Black Sea region of Turkey to determine the presence of Theileria and Babesia species of medical and veterinary importance. The ticks were removed from sheep and goats, pooled according to species and locations, and analyzed by PCR-based reverse line blot (RLB) and sequencing. A total of 2241 ixodid ticks belonging to 5 genus and 12 species were collected and divided into 310 pools. Infection rates were calculated as the maximum likelihood estimation (MLE) with 95% confidence intervals (CI). Of the 310 pools tested, 46 (14.83%) were found to be infected with Theileria or Babesia species, and the overall MLE of the infection rate was calculated as 2.27% (CI 1.67-2.99). The MLE of the infection rates were calculated as 0.691% (CI 0.171-1.78) in Haemaphysalis parva, 1.47% (CI 0.081-6.37) in Rhipicephalus sanguineus, 1.84% (CI 0.101-7.87) in Ixodes ricinus, 2.86% (CI 1.68-4.48) in Rhipicephalus turanicus, 5.57% (CI 0.941-16.3) in Hyalomma marginatum, and 6.2% (CI 4.02-9.02) in Rhipicephalus bursa. Pathogens identified in ticks included Theileria ovis, Babesia ovis, Babesia bigemina, and Babesia microti. Most tick pools were infected with a single pathogen. However, five pools displayed mixed infections with T. ovis and B. ovis. This study provides the first molecular evidence for the presence of B. microti in ticks in Turkey.

Molecular diagnostics for the food animal practitioner

Molecular diagnostics are becoming widely used as routine diagnostic tests performed by food animal practitioners. This article discusses the variations of several commonly performed molecular assays with regard to their molecular basis and the appropriate interpretation of the results. Applications of these methods are discussed in the context of infectious disease testing and genetic testing of food animal species.