Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks

Ravindran, Reghu; Hembram, Prabodh Kumar; Kumar, Gatchanda Shravan; Kumar, Karapparambu Gopalan Ajith; Deepa, Chundayil Kalarickal; Varghese, Anju

doi:10.1007/s00436-023-07792-9

Cited by 11 publications

(8 citation statements)

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“…Horizontal transmission refers to the spread of a parasite from the tick to the host and vice versa. In the case of a competent vector, horizontal transmission must be present in ticks [ 38 , 39 ]. Horizontal transmission of A. marginale from larvae, nymphs, and adult female ticks was detected when these ticks and their life stages fed on clean rabbits (uninfected rabbits).…”

Section: Discussionmentioning

confidence: 99%

Rearing of Rhipicephalus annulatus ticks on rabbits for the biological transmission of Anaplasma marginale

Ali,

Ahmad,

Ashraf

et al. 2024

Vet World

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Background and Aim: Anaplasma marginale is an obligate intraerythrocytic rickettsial parasite that infects cattle in tropical and subtropical regions. There is no evidence that A. marginale inoculation can be used to culture Rhipicephalus annulatus in rabbits. This study aimed to determine the molting of R. annulatus larvae, nymphs, and adults on rabbits as well as nymphs and adults of R. annulatus on calves with or without A. marginale. Transstadial, horizontal, and transovarial transmissions of A. marginale in R. annulatus reared on rabbits and calves were evaluated. Materials and Methods: Engorged female ticks were collected from field samples of A. marginale-infected and non-infected cattle. We divided the eight rabbits into two groups: A and B. Group A rabbits were infected with A. marginale through parenteral inoculation, whereas Group B rabbits were kept as a control. The “clean rabbits” in Group B were observed for tick rearing without A. marginale. Polymerase chain reaction was used to screen A. marginale in rabbits and stages of tick. The complete life cycle of R. annulatus with or without A. marginale was observed on rabbits. Results: A 6.5-day longer life cycle was observed in ticks harboring A. marginale than in ticks without A. marginale. To observe transstadial transmission, transstadial, horizontal, and transovarial transmissions of A. marginale in R. annulatus ticks were experimentally observed in one clean calf fed separately with infected nymphs and female adult ticks. Conclusion: We experimentally observed transovarian, transstadial, and transovarial transmission of A. marginale in R. annulatus ticks as a biological vector reared on calves and rabbits. We used rabbits as a model animal for rearing R. annulatus ticks and culture of A. marginale. Keywords: Anaplasma marginale, horizontal, rabbits, Rhipicephalus annulatus, transovarial, transstadial. Keywords: Anaplasma marginale, horizontal, rabbits, Rhipicephalus annulatus, transovarial, transstadial.

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Section: Discussionmentioning

confidence: 99%

Rearing of Rhipicephalus annulatus ticks on rabbits for the biological transmission of Anaplasma marginale

Ali,

Ahmad,

Ashraf

et al. 2024

Vet World

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“…The detection of LSDV in tick larvae highlights the potential of larvae as a source of infection for susceptible animals. Earlier reports have indicated that infected R. decoloratus females can vertically transmit the infection through their eggs and larvae to bovine hosts (Ravindran et al 2023). During summer, R. annulatus ticks can survive for up to 3-4 months without feeding, and at cooler temperatures, this period extends to as long as six months, potentially establishing the tick as a reservoir host for LSDV (Sprygin et al 2019).…”

Section: Characterization Of An Isolated Virus and Virus Detectionmentioning

confidence: 99%

Molecular Detection of Lumpy Skin Disease Virus in Naturally Infected Cattle and Buffaloes: Unveiling the Role of Tick Vectors in Disease Spread

Zeedan,

Abdalhamed,

Allam

et al. 2024

Preprint

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Lumpy Skin Disease (LSD) is a recently pervasive viral infection affecting cattle and buffaloes in Egypt, causing considerable economic losses in the animal sector. The aim of this study is to detect the potential impact role of hard ticks, Rhipicephalus annulets (R. boophilus annulets), in the spreading of Lumpy Skin Disease Virus (LSDV), with the characterization of isolates through molecular analysis. A total of 50 skin biopsies, 110 nasal swabs, and 129 blood samples were collected from cattle of different breeds and ages across different governorates in Egypt from November 2021 to June 2022. Additionally, 145 hard ticks of R. boophilus annulatus from different stages were collected. Multiplex PCR and real-time quantitative PCR (rt-qPCR) assays using SYBR Green were targets (P32, VP32, G protein, and viral fusion protein). They detected LSDV in 17 out of 30 cattle skin biopsies 56.6%), 1 out of 7 buffalo biopsies (14.3%), and only 5 blood samples from buffaloes (11.11%). Buffaloes appeared to be less susceptible to the virus than cattle; they may act as accidental hosts. We successfully isolated the virus from hard ticks and cattle exhibiting LSD clinical signs and harboring ticks in the chorioallantois membrane (CAM) route of specific pathogen-free, embryonated chicken eggs (SPF-ECE) and confirmed the isolates by multiplex PCR and rt-qPCR. Ct values ranging from 10 to 36.5 showed the amount of LSDV-DNA in different samples. The study's findings demonstrate the widespread circulation of LSDV in both cattle and buffaloes in Egypt and provide strong evidence that hard ticks (R. annulatus) ticks play a role in LSDV transmission in susceptible animals.

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“…This cycle can persist throughout the animal's lifespan depending on the host's immunity. Regarding their transmission, two distinct routes of transmission are involved: transstadial transmission from one stage of the tick's life cycle to the next and transovarial transmission (8)(9)(10). The life cycle of Theileria closely resembles that of Babesia, involving sexual gametogony followed by asexual sporogony in the tick gut.…”

Section: Introductionmentioning

confidence: 99%

“…Ovine babesiosis is a significant tick-borne disease affecting small ruminants, caused by various species such as B. ovis, B. motasi, B. crassa, B. taylori , and B. aktasi , among others ( 6 , 7 , 10 – 12 , 14 – 16 ). Taken into account, the most pathogenic species in sheep is B. ovis that causes malignant ovine babesiosis with fever, hemolytic anemia, hemoglobinuria, icterus and possible death others ( 6 , 7 , 10 – 12 , 17 , 18 ). Hemoglobinuria is uncommon, but it can occur in the advanced stages of the disease, leading to potential abortion in pregnant animals.…”

Section: Introductionmentioning

confidence: 99%

Microscopic and molecular detection of piroplasms among sheep in Upper Egypt

Dyab,

Mohamed,

Abdel-Aziz

et al. 2024

Front. Vet. Sci.

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IntroductionBlood parasites pose a significant threat to livestock production in southern Egypt, yet there is a scarcity of information regarding their circulation and epidemiology in sheep in this region. This study aimed to investigate the seroprevalence of blood parasite infections in sheep in Assiut governorate, Upper Egypt.MethodsA total of 400 blood samples were collected from sheep of varying ages and genders. The preliminary screening for the presence of piroplasms, mainly Babesia and Theileria spp., via microscopic examination, followed by investigation of the potential risk factors linked with the exposure to infection. Moreover, molecular identification of both parasites on some of positive samples was performed using PCR targeting Babesia 18S rRNA and Theileria annulata Tams1 gene.ResultsThe microscopic examination revealed that among the examined sheep, there was an overall prevalence of blood parasites at 44% (176 out of 400), with Babesia spp. observed in 14% (56 out of 400) and Theileria spp. in 30% (120 out of 400). Furthermore, the infection rate was non-significantly higher in young animals (50%) compared to adults (38.5%) (P = 0.246). Male sheep exhibited a significantly higher vulnerability to both parasites' infection (63.3%) compared to females (35.7%) (P = 0.011). Interestingly, the prevalence of both blood parasites was significantly higher during the cold season (66.1%) compared to the hot season (15.9%) (P = < 0.001). The molecular analysis identified the presence of Babesia ovis and Theileria annulata among a subsample of the positive sheep's bloods films. The identified species were recorded in the GenBank™ databases and assigned specific accession numbers (OQ360720 and OQ360719 for B. ovis), and (OP991838 for T. annulata).ConclusionsTaken together, this study confirms a high prevalence of piroplasmosis and offers epidemiological and molecular insights into blood parasites in sheep from Upper Egypt, highlighting the importance of detecting these parasites in various hosts and their competent vectors (ticks).

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Transovarial transmission of pathogenic protozoa and rickettsial organisms in ticks

Cited by 11 publications

References 148 publications

Rearing of Rhipicephalus annulatus ticks on rabbits for the biological transmission of Anaplasma marginale

Rearing of Rhipicephalus annulatus ticks on rabbits for the biological transmission of Anaplasma marginale

Molecular Detection of Lumpy Skin Disease Virus in Naturally Infected Cattle and Buffaloes: Unveiling the Role of Tick Vectors in Disease Spread

Microscopic and molecular detection of piroplasms among sheep in Upper Egypt

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