Perpetuation of the agent of human granulocytic ehrlichiosis in a deer tick-rodent cycle.

Telford, Sam R.; Dawson, Jacqueline E.; Katavolos, Paula; Warner, Cynthia K.; Kolbert, Christopher P.; Persing, David H.

doi:10.1073/pnas.93.12.6209

Cited by 460 publications

(398 citation statements)

References 30 publications

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“…Because there is no transovarial transmission of A. phagocytophilum infection must be acquired by the tick during larval or nymphal stages before it can be transferred to humans or domestic animals by adult ticks. Reported reservoirs are whitefooted mice (Peromyscus leucopus) in the eastern United States (Telford et al 1996), woodrats (Neotoma fuscipes) and squirrels (Sciurus spp.) in the western United States (Nicholson et al 1999;Foley et al 2002;Nieto and Foley 2008), and bank voles (Myodes glareolus) and wood mice (Apodemus agrarius) in the Europe and Asia (Blanco and Oteo 2002;Bown et al 2003;Cao et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Reservoir Competence of the Redwood Chipmunk (Tamias Ochrogenys) forAnaplasma Phagocytophilum

Nieto

Foley

2009

Vector-Borne and Zoonotic Diseases

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Granulocytic anaplasmosis (GA) is an emerging tick-transmitted disease that persists in rodent-Ixodes ricinuscomplex tick cycles across the Holarctic. Although the putative reservoir for anaplasmosis in the western United States is the dusky-footed woodrat (Neotoma fuscipes), this rodent was not shown reservoir-competent because of failure of infection from woodrats to other animals via ticks. Redwood chipmunks are common in habitats where Anaplasma phagocytophilum is common, have high PCR-and seroprevalence, and are infested with a diversity of Ixodes spp. ticks. Experimental infection of seven wild-caught A. phagocytophilum-negative redwood chipmunks induced persistent periods of recurrent rickettsemia during the persistent phase of infection. Of three animals for which xenodiagnosis was attempted, all successfully infected pools of I. pacificus larvae during the primary rickettsemia. We show that chipmunks are reservoir-competent for GA and may be important for maintaining infection in nature.

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Section: Introductionmentioning

confidence: 99%

Reservoir Competence of the Redwood Chipmunk (Tamias Ochrogenys) forAnaplasma Phagocytophilum

Nieto

Foley

2009

Vector-Borne and Zoonotic Diseases

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“…Granulocytotropic ehrlichiae have a broad host range including humans, 1 horses, 2 dogs, 3 cats, 4,5 small rodents, 6,7 black bears (Walls J and others, unpublished data), cattle and sheep, 8,9 and deer. 10 The development of clinical signs appears to be largely host-species dependent.…”

mentioning

confidence: 99%

A simian model of human granulocytic ehrlichiosis.

Foley

Lerche²,

Dumler

et al. 1999

The American Journal of Tropical Medicine and Hygiene

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Abstract. Following intravenous inoculation with horse blood-infected with the agent of human granulocytic ehrlichiosis (HGE) from a human fatality, two rhesus macaques (Macaca mulatta) exhibited pyrexia and lethargy on days 4-12 postinfection (PI). Hematology revealed neutropenia, thrombocytopenia, and anemia, with ehrlichial morulae in monocytes and neutrophils on days 4-12. Blood was polymerase chain reaction (PCR)-positive on days 4-12 and bone marrow was PCR-positive on day 11. There was a minor increase in gamma-glutamyl transpeptidase on day 12 and serum interferon-␥ levels increased by day 18. Seroconversion occurred on day 20 PI to a titer of 100 by day 22. Western blot bands characteristic of HGE included 25-, 44-, 80-, 94-, 105-, and 125-kD 10 The development of clinical signs appears to be largely host-species dependent. An early attempt to infect non-human primates with Ehrlichia equi was successful based on visualization of ehrlichial inclusions within the cytoplasm of neutrophils.3 However, that study was hampered by the lack of some diagnostic procedures such as the polymerase chain reaction (PCR) and DNA sequencing, cytokine assays, and other immunologic assays. Moreover, the investigators did not know at that time that E. equi or its close relative, the agent of human granulocytic ehrlichiosis (HGE), was capable of producing life-threatening disease in humans. 1 In the present study, we report successful experimental infection of rhesus macaques with the HGE agent from a severely ill human case. This animal model of human disease is important for further studies of HGE diagnosis, management, and pathogenesis. MATERIALS AND METHODS Animals and inoculation.Three rhesus macaques were pre-screened for ehrlichiosis by serology and E. equi-specific PCR. Monkey 312 was a 16-year-old reproductively intact female who had been used previously for breeding and a teratogenesis study (zinc deprivation). Monkey 121 was a 17-year-old intact female with a history of use for breeding and anti-progestin drug studies. Monkey 324 was a 14-yearold intact female from the breeding colony. Monkeys 121 and 312 were inoculated intravenously with fresh horse blood containing 2 ϫ 10 6 neutrophils of which 15% contained HGE agent strain BDS inclusions (morulae); monkey 324 was control-inoculated with 2 ϫ 10 6 uninfected horse neutrophils. All monkeys were monitored twice a day for clinical signs of disease, including lethargy, inappetance, and depression. Rectal temperature was assessed at the time of each blood sample collection. Blood samples were collected every two days into tubes containing EDTA for Wright-Giemsa staining and PCR and without anticoagulant for serology and serum chemistry. Bone marrow aspirates were performed on days 3, 11, and 14 postinfection (PI) and submitted for cytology and PCR. On day 21 PI, monkeys 121 and 324 were killed with an intravenous overdose of barbiturate and necropsied. Samples from tissues were either snap-frozen in liquid nitrogen for PCR or fixed overnight in 10% buffered forma...

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“…14,15 White-tailed deer are potential reservoirs for E. chaffeensis in the southern states, [16][17][18] and white-footed mice are reservoirs of the HGE agent in the northeastern states. 19 The reservoirs of the etiologic agents of human ehrlichioses in California are unknown.…”

mentioning

confidence: 99%

Detection of the agents of human ehrlichioses in ixodid ticks from California.

Kramer¹,

Randolph²,

Hui³

et al. 1999

The American Journal of Tropical Medicine and Hygiene

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Abstract.A study was conducted in northern California to estimate the prevalence and distribution in ixodid ticks of the rickettsial agents of human monocytic (HME) and human granulocytic (HGE) ehrlichioses. More than 650 ixodid ticks were collected from 17 sites in six California counties over a 15-month period. Ehrlichia chaffeensis, the causative agent of HME, was detected by a nested polymerase chain reaction (PCR) in Ixodes pacificus (minimum infection rate [MIR] ϭ 13.3%) and Dermacentor variabilis (infection rateϭ20.

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Perpetuation of the agent of human granulocytic ehrlichiosis in a deer tick-rodent cycle.

Cited by 460 publications

References 30 publications

Reservoir Competence of the Redwood Chipmunk (Tamias Ochrogenys) forAnaplasma Phagocytophilum

Reservoir Competence of the Redwood Chipmunk (Tamias Ochrogenys) forAnaplasma Phagocytophilum

A simian model of human granulocytic ehrlichiosis.

Detection of the agents of human ehrlichioses in ixodid ticks from California.

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