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Bacterial arthropod-borne pathogens can often cause fever in Africa, but rural laboratories in these settings are usually too basic to provide a precise picture of their epidemiological impact. Our aim was to determine the prevalence of bacterial pathogens in fleas and lice in a rural area of southeast Ethiopia. Between July and November 2013, we extracted DNA from 91 fleas ( Ctenocephalides felis [ n  = 50; 54.9%], Pulex irritans [ n  = 37; 40.1%], and C. canis [ n  = 4; 4.4%] and 30 lice ( Pediculus humanus capitis [ n  = 16; 53.3%] and Pediculus humanus humanus [ n  = 14; 46.7%]), using two quantitative PCR (qPCR) analyses to look for bacteria from the genera: Anaplasma , Bartonella , Borrelia , Coxiella , Ehrlichia , Francisella , and Rickettsia . Of the 91 fleas analyzed, pathogens were present in 79 (86.8%), including Rickettsia felis ( n  = 41; 45%), Anaplasma platys ( n  = 40; 44.0%), Rickettsia monacensis ( n  = 2; 2.2%), Ehrlichia muris- like agent ( n  = 1; 1.1%), and Bartonella clarridgeiae ( n  = 1; 1.1%). P. irritans was the flea species most frequently infected with A. platys (67.7%), followed by C. felis (30.7%) ( p  < 0.001). Of the 30 lice identified, pathogens were present in 7 (23.3%): Bartonella quintana ( n  = 4; 16.7%), E. muris ( n  = 2, 6.7%), and Borrelia recurrentis ( n  = 1, 3.3%). Thus, in this rural area of Africa, fleas and lice can transmit parasitic pathogens to humans, causing febrile symptoms.

Ehrlichiosis and anaplasmosis are important emerging tickborne zoonoses that affect both humans and animals. Knowledge of the geographic distribution and prevalence of Ehrlichia spp. and Anaplasma phagocytophilum in Wisconsin is important information as a baseline for future comparisons. Reported human cases between 2009 and 2015 were identified using the Wisconsin Electronic Disease Surveillance System (WEDSS) and mapped by county of residence. Vector surveillance was established using ticks collected from animals by partners, including veterinary medical clinics, domestic animal shelters, and wildlife rehabilitation centers from 40 Wisconsin counties. A total of 1835 Ixodes scapularis tick specimens (larvae, nymphs, and adults) were collected from 18 different domestic and wildlife species from July 2011 to November 2015. An additional 1136 nymphs were collected by drag sampling at 23 locations in 19 counties in 2015. A real-time PCR assay that detects and distinguishes several Ehrlichia species, including a pathogenic Ehrlichia muris-like agent (EMLA), and A. phagocytophilum was performed on adult and nymphal ticks. A total of 757 I. scapularis ticks (predominately adults) were tested from animal collections, with 67 (8.9%) individuals positive for A. phagocytophilum and 22 (2.9%) positive for EMLA DNA. Of the 1150 questing nymphs, 62 (5.4%) were positive for A. phagocytophilum and 10 (0.9%) were positive for EMLA DNA. Specimens of I. scapularis that were positive for A. phagocytophilum were found in 27 of the 33 counties surveyed. Specimens that were positive for EMLA were less common and were found in nine counties. This study provides the first statewide survey of I. scapularis ticks for these pathogens and indicates that the risk of human exposure is widely distributed.

The variations in prevalence levels of two tick-borne rickettsial pathogens, Ehrlichia chaffeensis and Ehrlichia Ewingii, in a periurban environment were evaluated along with their ecological determinants. Tick life stage and sex, month of tick collection, landscape fragmentation, and ecological covariates specific to pasture and woodland sites were considered as explanatory covariates. Questing lone star ticks (Amblyomma americanum) were collected by flagging for an hour once every week during mid-April through mid-August in years 2013 and 2014. A total of 4357 adult and nymphal ticks (woodland = 2720 and pasture = 1637) were collected and assessed for pathogen prevalence by molecular methods. Female A. americanum ticks were more infected with E. chaffeensis than males or nymphs in woodland areas [♂ = 6.05%; ♀ = 12.0%; nymphs = 2.09%] and pastures [♂ = 8.05%; ♀ = 12.03%; nymphs = 3.33%], and the prevalence was influenced by edge density in the landscape. Higher E. ewingii infection was noted among female A. americanum ticks within woodland areas [♂ = 1.89%; ♀ = 2.14%; nymphs = 1.57%], but no such difference was evident in pastures [♂ = 1.03%; ♀ = 1.33%; nymphs = 1.12%]. Prevalence of E. ewingii was influenced by edge contrast index, and the percentage of pasture perimeter that was less than 20 meters from woodland areas. This study elucidates the complexity of tick-borne pathogen ecology and points to the need for further studies on the role of reservoir hosts, particularly that played by small vertebrates, which is not fully understood in the region.

We collected 2460 Haemaphysalis longicornis ticks from vegetation in Jiaonan County, Shandong Province, in June of 2013 and Daishan County, Zhejiang Province, China, in May of 2015. The tick DNA was subsequently amplified with nested polymerase chain reaction using Ehrlichia common 16S rRNA gene primers and Ehrlichia ewingii species-specific groEL and gltA primers. We found 0.4% (3/780) of the ticks from Zhejiang Province contained Ehrlichia DNA that was different from all known Ehrlichia species, but most closely related to E. ewingii. We concluded that a novel Ehrlichia species exists in H. longicornis ticks in China.

The prevalence and distribution of Anaplasma and Ehrlichia were estimated in 201 symptomatic dogs from Panama by nested PCR and DNA sequencing of the 16S rRNA gene. In total, 163 dogs (70.6%; 163/201) were infected with either Anaplasma or Ehrlichia. On the basis of PCR results, the majority of cases were infected with E. canis (64.2%; 129/201) followed by 21.4% (43/201) with A. platys, whereas 7.5% (15/201) had Anaplasma/Ehrlichia co-infections. Further analyses of 16S rDNA partial sequences show sequence homology with E. canis and A. platys from other countries. Hematology findings from 79 E. canis PCR-positive dogs included anemia (74.7%), thrombocytopenia (81.9%), macroplatelets (29.1%), and leukopenia (6.3%). Among 16 A. platys PCR-positive dogs with available hematology, 62.5% were anemic, 75% had thrombocytopenia, and 100% had macroplatelets. On the basis of E.canis serology (enzyme-linked immunosorbent assay [ELISA]) (n=92 dogs), 30 dogs that were seropositive for E. canis were also PCR-positive, whereas among seronegatives (n=62), 10 were PCR-positive for E. canis. This study provides the first characterization of canine anaplasmosis and ehrlichiosis infections in Panama and is important to veterinary public health and comparative studies of these pathogens in the Americas.

Ehrlichia and Anaplasma species are tick-transmitted obligately intracellular bacteria that commonly cause disease in dogs worldwide. In addition to causing disease in canines, Ehrlichia chaffeensis, Ehrlichia ewingii, and Anaplasma phagocytophilum are responsible for emerging and life-threatening human zoonoses in the United States. We previously reported a high prevalence of E. canis infection in Cameroonian dogs based on serologic and molecular evidence. This study was undertaken to determine the Ehrlichia species (E. canis, E. chaffeensis, E. ewingii) present in Rhipicephalus sanguineus ticks (n = 92) collected from those dogs (n = 51). Ehrlichial DNA was detected by real-time polymerase chain reaction (PCR) in 28 (30%) unengorged R. sanguineus ticks attached to dogs. E. canis, the causative agent of canine monocytic ehrlichiosis, was detected in 19 (21%) ticks from 15 dogs, E. ewingii was detected in six (6%) ticks from 6 dogs, and E. chaffeensis, the etiologic agent of human monocytotropic ehrlichiosis, was detected in 4 (4%) ticks. Notably, 2 ticks were coinfected with E. chaffeensis and E. canis, one tick with E. canis and E. ewingii, and one tick with E. chaffeensis and E. ewingii. These findings further support our previous conclusion that multiple Ehrlichia species are present in Cameroon and identify R. sanguineus ticks primarily infected with E. canis, but suggest that they may be infected with and transmit other ehrlichial agents in Cameroon, potentially to humans.

Raccoons (Procyonis lotor) and opossums (Didelphis virginianus) acquired from six contiguous counties in the Piedmont physiographic region of Georgia were investigated for their potential role in the epidemiology of ehrlichial and anaplasmal species. Serum was tested by indirect fluorescent antibody (IFA) assay for the presence of antibodies reactive to Ehrlichia chaffeensis, E. canis, and Anaplasma phagocytophilum (HGA agent). Nested polymerase chain reaction (PCR) assay was used to test whole blood or white blood cell preparations for the presence of Ehrlichia and Anaplasma spp. 16S rRNA (rDNA) gene fragments. In addition, ticks were collected from these animals and identified. Twenty-three of 60 raccoons (38.3%) had E. chaffeensis-reactive antibodies (>1:64), 13 of 60 raccoons (21.7%) had E. canis-reactive antibodies, and one of 60 raccoons (1.7%) had A. phagocytophilum- reactive antibodies. A sequence confirmed E. canis product was obtained from one of 60 raccoons and a novel Ehrlichia-like 16S rDNA sequence was detected in 32 of 60 raccoons. This novel sequence was most closely related to an Ehrlichia-like organism identified from Ixodes ticks and rodents in Asia and Europe. Raccoons were PCR negative for E. chaffeensis and E. ewingii DNA. Five tick species, including Dermacentor variabilis, Amblyomma americanum, Ixodes texanus, I. cookei, and I. scapularis, were identified from raccoons and represent potential vectors for the ehrlichiae detected. Opossums (n = 17) were free of ticks and negative on all IFA and PCR assays. This study suggests that raccoons are potentially involved in the epidemiology of multiple ehrlichial organisms with known or potential public health and veterinary implications.

The last half of the 20th Century witnessed an increase in the occurrence and recognition of urban zoonoses caused by members of the genera Bartonella, Coxiella, Ehrlichia, and Rickettsia, all traditionally considered to be members of the family Rickettsiaceae. In recent years, new human pathogens (Bartonella elizabethae, Bartonella henselae, and Rickettsia felis) have been recognized in urban environments. Other newly recognized pathogens (Ehrlichia chaffeensis and Ehrlichia phagocytophila in the United States) have sylvan zoonotic cycles but are present in urban areas because their vertebrate hosts and associated ectoparasitic arthropod vectors are able to survive in cities. Still other agents, which were primarily of historical importance (Bartonella quintana) or have not traditionally been associated with urban environments (Rickettsia rickettsii), have been recognized as causes of human disease in urban areas. Some diseases that have traditionally been associated with urban environments, such as rickettsialpox (caused by Rickettsia akari) and murine typhus (caused by Rickettsia typhi), still occur in large cities at low or undetermined frequencies and often go undetected, despite the availability of effective measures to diagnose and control them. In addition, alternate transmission cycles have been discovered for Coxiella burnetii, Rickettsia prowazekii, and R. typhi that differ substantially from their established, classic cycles, indicating that the epidemiology of these agents is more complex than originally thought and may be changing. Factors leading to an increase in the incidence of illnesses caused by these bacteria in urban areas include societal changes as well as intrinsic components of the natural history of these organisms that favor their survival in cities. Transovarial and transstadial transmission of many of the agents in their arthropod hosts contributes to the highly focal nature of many of the diseases they cause by allowing the pathogens to persist in areas during adverse times when vertebrate amplifying hosts may be scarce or absent. Domesticated animals (primarily cats, dogs, and livestock) or commensal rodents [primarily Norway rats (Rattus norvegicus) and house mice (Mus musculus)] can serve as vertebrate amplifying hosts and bring these agents and their ectoparasitic arthropod vectors into direct association with humans and help maintain transmission cycles in densely populated urban areas. The reasons for the increase in these urban zoonoses are complex. Increasing population density worldwide, shifts in populations from rural areas to cities, increased domestic and international mobility, an increase in homelessness, the decline of inner-city neighborhoods, and an increase in the population of immunosuppressed individuals all contribute to the emergence and recognition of human diseases caused by these groups of agents. Due to the focal nature of infections in urban areas, control or prevention of these diseases is possible. Increased physician awareness and public health surveillance support will be required to detect and treat existing urban infections caused by these agents, to determine the disease burden caused by them, to design and implement control programs to combat and prevent their spread, and to recognize emerging or resurging infections caused by members of these genera as they occur.