Detection of Theileria orientalis genotypes in Haemaphysalis longicornis ticks from southern Australia

Abstract Background Theileria orientalis is a tick-borne hemoparasite that causes anemia, ill thrift, and death in cattle globally. The Ikeda strain of T.orientalis is more virulent than other strains, leading to severe clinical signs and death of up to 5% of affected animals. Within the Asia–Pacific region, where it affects 25% of Australian cattle, T.orientalis Ikeda has a significant economic impact on the cattle industry. In 2017, T.orientalis Ikeda was detected in a cattle herd in Albermarle County, Virginia, United States. Months earlier, the U.S. was alerted to the invasion of the Asian longhorned tick, Haemaphysalis longicornis, throughout the eastern U.S. Abundant H.longicornis ticks were identified on cattle in the T.orientalis-affected herd in VA, and a subset of ticks from the environment were PCR-positive for T.orientalis Ikeda. A strain of T.orientalis from a previous U.S. outbreak was not transmissible by H.longicornis; however, H.longicornis is the primary tick vector of T.orientalis Ikeda in other regions of the world. Thus, the objective of this study was to determine whether invasive H.longicornis ticks in the U.S. are competent vectors of T.orientalis Ikeda. Methods Nymphal H.longicornis ticks were fed on a splenectomized calf infected with the VA-U.S.-T.orientalis Ikeda strain. After molting, a subset of adult ticks from this cohort were dissected, and salivary glands assayed for T.orientalis Ikeda via qPCR. The remaining adult ticks from the group were allowed to feed on three calves. Calves were subsequently monitored for T.orientalis Ikeda infection via blood smear cytology and PCR. Results After acquisition feeding on a VA-U.S.-T.orientalis Ikeda-infected calf as nymphs, a subset of molted adult tick salivary glands tested positive by qPCR for T.orientalis Ikeda. Adult ticks from the same cohort successfully transmitted T.orientalis Ikeda to 3/3 naïve calves, each of which developed parasitemia reaching 0.4–0.9%. Conclusions Our findings demonstrate that U.S. H.longicornis ticks are competent vectors of the VA-U.S.-T.orientalis Ikeda strain. This data provides important information for the U.S. cattle industry regarding the potential spread of this parasite and the necessity of enhanced surveillance and control measures.

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Changes in the Levels of Theileria orientalis Ikeda Type Infection in Haemaphysalis longicornis Nymphs over a Six-Month Period

Journal of Parasitology ◽

10.1645/20-177 ◽

2021 ◽

Vol 107 (5) ◽

Author(s):

Yilin Zhao ◽

Kevin E. Lawrence ◽

Maria Minor ◽

Kristene Gedye ◽

Bo Wang ◽

...

Keyword(s):

Haemaphysalis Longicornis ◽

Theileria Orientalis ◽

Type Infection

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A U.S. Isolate of Theileria Orientalis, Ikeda Genotype, is Transmitted to Cattle by the Invasive Asian Longhorned Tick, Haemaphysalis Longicornis

10.21203/rs.3.rs-90827/v1 ◽

2020 ◽

Author(s):

Kelcey D Dinkel ◽

David Herndon ◽

Susan M Noh ◽

Kevin K Lahmers ◽

S. Michelle Todd ◽

...

Keyword(s):

Salivary Glands ◽

Clinical Signs ◽

Adult Tick ◽

Control Measures ◽

Asia Pacific ◽

Haemaphysalis Longicornis ◽

Cattle Industry ◽

Theileria Orientalis ◽

And Control ◽

The U.S

Abstract BACKGROUNDTheileria orientalis is a tick-borne hemoparasite that causes anemia, ill thrift, and death in cattle globally. The Ikeda strain of T. orientalis is more virulent than other strains, leading to severe clinical signs and death in less than 5% of affected animals. Within the Asia-Pacific region, where it affects 25% of Australian cattle, T. orientalis Ikeda has a significant economic impact on the cattle industry. In 2017, T. orientalis Ikeda was detected in a cattle herd in Albermarle County, Virginia, United States. Months earlier, the U.S. was alerted to the invasion of the Asian longhorned tick, Haemaphysalis longicornis, throughout the eastern U.S. Abundant H. longicornis ticks were identified on cattle in the T. orientalis-affected herd in VA, and a subset of ticks from the environment were PCR-positive for T. orientalis Ikeda. A strain of T. orientalis from a previous U.S. outbreak was not transmissible by H. longicornis; however, H. longicornis is the primary tick vector of T. orientalis Ikeda in other regions of the world. Thus, the objective of this study was to determine whether invasive H. longicornis ticks in the U.S. are competent vectors of T. orientalis Ikeda. METHODSNymphal H. longicornis ticks were fed on a splenectomized calf infected with the VA-U.S.-T. orientalis Ikeda strain. After molting, a subset of adult ticks from this cohort were dissected, and salivary glands assayed for T. orientalis Ikeda via qPCR. The remaining adult ticks from the group were allowed to feed on three calves. Calves were subsequently monitored for T. orientalis Ikeda infection via blood smear cytology and PCR.RESULTSAfter acquisition feeding on a VA-U.S.-T. orientalis Ikeda-infected calf as nymphs, a subset of molted adult tick salivary glands tested positive by qPCR for T. orientalis Ikeda. Adult ticks from the same cohort successfully transmitted T. orientalis Ikeda to 3/3 naïve calves, each of which developed parasitemia reaching 0.4-0.9%.CONCLUSIONSOur findings demonstrate that U.S. H. longicornis ticks are competent vectors of the VA-U.S.-T. orientalis Ikeda strain. This data provides important information for the U.S. cattle industry regarding the potential spread of this parasite and the necessity of enhanced surveillance and control measures.

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Genotypic Analysis of Piroplasms and Associated Pathogens from Ticks Infesting Cattle in Korea

Microorganisms ◽

10.3390/microorganisms8050728 ◽

2020 ◽

Vol 8 (5) ◽

pp. 728 ◽

Cited By ~ 1

Author(s):

Min-Goo Seo ◽

Oh-Deog Kwon ◽

Dongmi Kwak

Keyword(s):

Surface Protein ◽

Molecular Characteristics ◽

Haemaphysalis Longicornis ◽

Theileria Orientalis ◽

Cattle Ticks ◽

Genotypic Analysis ◽

Clinical Complexity ◽

Tropical Areas ◽

Anaplasma Bovis ◽

Major Piroplasm Surface Protein

Tick-borne pathogens (TBPs) impose an important limitation to livestock production worldwide, especially in subtropical and tropical areas. Earlier studies in Korea have examined TBPs residing in ticks and animals; however, information on multiple TBPs in ticks infesting cattle is lacking. This study assessed the prevalence of TBPs in ticks parasitizing cattle. A total of 576 ticks, including 340 adults and 236 nymphs, were collected from cattle in Korea between 2014 and 2018. All ticks collected were identified as Haemaphysalis longicornis based on their morphological and molecular characteristics. Among piroplasms and other tick-associated pathogens, seven TBP genes, namely Theileria orientalis (5.0%), Anaplasma bovis (2.3%), Anaplasma capra (4.7%), Anaplasma phagocytophilum-like Anaplasma spp. (APL) clades A (1.9%) and B (0.5%), Ehrlichia canis (1.6%), and Candidatus Rickettsia longicornii (17.5%), were detected. Bartonella spp. and severe fever with thrombocytopenia syndrome virus were not found. To our knowledge, this is the first study to report the presence of the pathogens T. orientalis major piroplasm surface protein genotypes 3 and 7, A. capra, and APL in ticks from Korea. Cattle ticks may be maintenance hosts for many TBPs, and veterinary and medical clinicians should be aware of their high probability of infection and clinical complexity in humans.

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Rapid Discovery and Detection of Haemaphysalis longicornis through the Use of Passive Surveillance and Collaboration: Building a State Tick-Surveillance Network

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18157980 ◽

2021 ◽

Vol 18 (15) ◽

pp. 7980

Author(s):

Rebecca T. Trout Fryxell ◽

Dené N. Vann ◽

Rebecca A. Butler ◽

Dave J. Paulsen ◽

Jennifer G. Chandler ◽

...

Keyword(s):

Adult Stage ◽

Companion Animals ◽

Federal State ◽

Haemaphysalis Longicornis ◽

Passive Surveillance ◽

Babesia Species ◽

Female Adult ◽

Surveillance Network ◽

Theileria Orientalis ◽

First Time

Between March 2019 and February 2020, Asian long-horned ticks (Haemaphysalis longicornis Neumann, 1901) were discovered and collected for the first time in one middle and seven eastern Tennessee counties, facilitated by a newly developed passive and collaborative tick-surveillance network. Network collaborators included federal, state, county, university, and private resource personnel working with companion animals, livestock, and wildlife. Specimens were collected primarily from dogs and cattle, with initial detections of female adult stage ticks by stakeholders associated with parasitology positions (e.g., entomologists and veterinary parasitologists). Initial county tick detections were confirmed with morphological and molecular identifications, and then screened for the presence of animal-associated pathogens (Anaplasma marginale, Babesia species, Ehrlichia species, and Theileria orientalis), for which all tests were negative. Herein, we describe the identification and confirmation of these tick specimens as well as other results of the surveillance collaboration.

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Theileria orientalis Ikeda in host-seeking Haemaphysalis longicornis in Virginia, U.S.A.

Ticks and Tick-borne Diseases ◽

10.1016/j.ttbdis.2020.101450 ◽

2020 ◽

Vol 11 (5) ◽

pp. 101450 ◽

Cited By ~ 5

Author(s):

Alec T. Thompson ◽

Seth White ◽

David Shaw ◽

Andrea Egizi ◽

Kevin Lahmers ◽

...

Keyword(s):

Haemaphysalis Longicornis ◽

Theileria Orientalis ◽

Host Seeking

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Merozoites of Theileria Orientalis Buffeli Reduce Parasitosis Following Challenge by Ticks Infested with T.Orientalis Ikeda

10.21203/rs.3.rs-92267/v1 ◽

2020 ◽

Author(s):

David Emery ◽

Susan de Burgh ◽

Therese Hoang Hieu Hanh Dinh ◽

Peter Rolls ◽

Phillip Carter

Keyword(s):

Field Experience ◽

Carrier State ◽

Clinical Disease ◽

Haemaphysalis Longicornis ◽

Bovine Blood ◽

Theileria Orientalis ◽

Associated Production ◽

And Control ◽

Production Losses

Abstract Background: An investigation aimed to confirm whether immunisation with the “benign” buffeli genotype of Theileria orientalis could reduce the parasitosis of the virulent ikeda genotype. Methods: Calves were inoculated intravenously or subcutaneously with bovine blood containing merozoites of T.orientalis buffeli. When recipients became positive, they and control animals were challenged with unfed nymphs of Haemaphysalis longicornis ticks infested as larvae with T.orientalis ikeda. Results: All calves became positive for the challenge within 12 days after tick application. In the immunised calves, the first wave of parasitosis with T.orientalis ikeda from 4-6 weeks was reduced significantly by >80% before the infestation declined into the carrier state by 9 weeks. Conclusions: The results confirm the field experience with theileriosis in endemic zones where the carrier state appears to prevent clinical disease despite repeated, seasonal tick infestations with virulent genotypes of the parasite. This method offers a means to reduce the severity of the first wave of theilerial parasitosis after tick challenge and recover associated production losses.

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