Hayley D. Yaglom

Rickettsia parkeri Rickettsiosis, Arizona, USA

The likely vector was Amblyomma triste, a Neotropical tick species only recently recognized in the United States.

Fatal Rocky Mountain Spotted Fever along the United States–Mexico Border, 2013–2016

Although these cases are uncommon, early recognition and prompt initiation of appropriate treatment are vital for averting severe illness and death.

Rickettsia parkeri (Rickettsiales: Rickettsiaceae) Detected in Ticks of the Amblyomma maculatum (Acari: Ixodidae) Group Collected from Multiple Locations in Southern Arizona.

Abstract Rickettsia parkeri is an emerging human pathogen transmitted by Amblyomma ticks in predominately tropical and subtropical regions of the western hemisphere. In 2014 and 2015, one confirmed case and one probable case of R. parkeri rickettsiosis were reported from the Pajarita Wilderness Area, a semi-arid mountainous region in southern Arizona. To examine more closely the potential public health risk of R. parkeri in this region, a study was initiated to investigate the pervasiveness of Amblyomma maculatum Koch group ticks in mountainous areas of southern Arizona and to ascertain the infection frequencies of R. parkeri in these ticks. During July 2016, a total of 182 adult ticks were collected and evaluated from the Pajarita Wilderness Area in Santa Cruz County and two additional sites in Cochise and Santa Cruz counties in southern Arizona. DNA of R. parkeri was detected in a total of 44 (24%) of these ticks. DNA of “Candidatus Rickettsia andeanae” and Rickettsia rhipicephali was detected in three (2%) and one (0.5%) of the samples, respectively. These observations corroborate previous collection records and indicate that established populations of A. maculatum group ticks exist in multiple foci in southern Arizona. The high frequency of R. parkeri in these tick populations suggests a public health risk as well as the need to increase education of R. parkeri rickettsiosis for those residing, working in, or visiting this area.

Exposure Characteristics of Hantavirus Pulmonary Syndrome Patients, United States, 1993–2015

Those at highest risk are persons in occupations with potential for rodent exposure and American Indian women 40–64 years of age.

Animal Assisted Activity with Older Adult Retirement Facility Residents: The PAWSitive Visits Program

Animal assisted activity (AAA) programs offer widespread physiological, social, and emotional benefits to recipient populations, particularly older adults. While AAA is common in nursing homes, it is less common in retirement residences where individuals are often suffering from the stress of relocating and transitioning to a more dependent lifestyle. PAWSitive Visits (PV) is a weekly AAA visitation program conducted in a group-setting at a Midwestern retirement residence that brings an array of domestic and exotic animal species for the residents to interact with. PV strives to provide educational opportunities for the residents, facilitating their social engagement, eliciting memories of previously owned pets, and offering intergenerational activities. It also provides meaningful learning experiences for students (e.g., nursing and veterinary medical students) who affiliate with the program. The conceptual model for PV is the threefold notion of attachment, reciprocity, and unconditional acceptance that animals offer older adults. PV is a unique and successful program, coordinated in a manner that ensures the health and safety of both animal and human counterparts, while providing residents with experiences that enhance their well-being.

Development of an enzyme immunoassay for detection of antibodies against Coccidioides in dogs and other mammalian species

Coccidioides is a soil-dwelling fungus that causes coccidioidomycosis, a disease also known as Valley fever, which affects humans and a variety of animal species. Recent findings of Coccidioides in new, unexpected areas of the United States have demonstrated the need for a better understanding of its geographic distribution. Large serological studies on animals could provide important information on the geographic distribution of this pathogen. To facilitate such studies, we used protein A/G, a recombinant protein that binds IgG antibodies from a variety of mammalian species, to develop an enzyme immunoassay (EIA) that detects IgG antibodies against Coccidioides in a highly sensitive and high-throughput manner. We showed the potential of this assay to be adapted to multiple animal species by testing a collection of serum and/or plasma samples from dogs, mice, and humans with or without confirmed coccidioidomycosis. We then evaluated the performance of the assay in dogs, using sera from dogs residing in a highly endemic area, and found seropositivity rates significantly higher than those in dogs of non-endemic areas. We further evaluated the specificity of the assay in dogs infected with other fungal pathogens known to cross-react with Coccidioides. Finally, we used the assay to perform a cross-sectional serosurvey investigating dogs from Washington, a state in which infection with Coccidioides has recently been documented. In summary, we have developed a Coccidioides EIA for the detection of antibodies in canines that is more sensitive and has higher throughput than currently available methods, and by testing this assay in mice and humans, we have shown a proof of principle of its adaptability for other animal species.

Serologic assessment for exposure to spotted fever group rickettsiae in dogs in the Arizona-Sonora border region

Rocky Mountain spotted fever (RMSF) is a severe tick‐borne rickettsial illness. In the south‐western United States and Mexico, RMSF displays unique epidemiologic and ecologic characteristics, including Rhipicephalus sanguineus sensu lato (brown dog tick) as the primary vector. Expansion and spread of the disease from hyperendemic regions of Arizona or Mexico to new areas is a key public health concern. Dogs are thought to play an important role in the emergence and circulation of R. rickettsii in these regions and are often one of earliest indicators of RMSF presence. A canine serosurvey was conducted in 2015 among owned and stray dogs at rabies clinic and animal shelters in three southern Arizona counties where RMSF had not previously been identified. Of the 217 dogs sampled, 11 (5.1%) tested positive for spotted fever group rickettsia (SFGR) IgG antibodies, with seropositivity ranging from 2.9% to 12.2% across the three counties. Large dogs were significantly more likely than small dogs to have positive titres reactive with R. rickettsii; no additional statistically significant relationships were observed between seropositivity of canine age, sex, neuter or ownership status. In addition, 17 (7.8%) dogs had ticks attached at the time of sampling, and stray dogs were significantly more likely to have ticks present than owned dogs (p < 0.001). All 57 ticks collected were identified as Rh. sanguineus s.l., and four (7%) had DNA evidence of genera‐wide Rickettsia species. The results of this project demonstrated canine seroprevalence levels lower than those previously reported from dogs in highly endemic areas, indicating a low risk of SFGR transmission to humans in the southern Arizona border region at this time. Continued surveillance is critical to identify SFGR emergence in new geographic regions and to inform prevention efforts for humans and dogs in those areas.

CHLAMYDIA PSITTACI IN FERAL ROSY-FACED LOVEBIRDS (AGAPORNIS ROSEICOLLIS) AND OTHER BACKYARD BIRDS IN MARICOPA COUNTY, ARIZONA, USA

Abstract:  In 2013, a mortality event of nonnative, feral Rosy-faced Lovebirds (Agapornis roseicollis) in residential backyards in Maricopa County, Arizona, US was attributed to infection with Chlamydia psittaci. In June 2014, additional mortality occurred in the same region. Accordingly, in August 2014 we sampled live lovebirds and sympatric bird species visiting backyard bird feeders to determine the prevalence of DNA and the seroprevalence of antibodies to C. psittaci using real-time PCR-based testing and elementary body agglutination, respectively. Chlamydia psittaci DNA was present in conjunctival-choanal or cloacal swabs in 93% (43/46) of lovebirds and 10% (14/142) of sympatric birds. Antibodies to C. psittaci were detected in 76% (31/41) of lovebirds and 7% (7/102) of sympatric birds. Among the sympatric birds, Rock Doves (Columba livia) had the highest prevalence of C. psittaci DNA (75%; 6/8) and seroprevalence (25%; 2/8). Psittacine circovirus 1 DNA was also identified, using real-time PCR-based testing, from the same swab samples in 69% (11/16) of species sampled, with a prevalence of 80% (37/46) in lovebirds and 27% (38/142) in sympatric species. The presence of either Rosy-faced Lovebirds or Rock Doves at residential bird feeders may be cause for concern for epizootic and zoonotic transmission of C. psittaci in this region.

Evidence of Likely Autochthonous Transmission of Chagas Disease in Arizona

A healthy 16-year-old girl born and raised in Tucson, AZ, had screening and confirmatory testing revealing Chagas disease; clinical evaluation established that she had the indeterminate form of chronic Chagas disease with evidence of likely autochthonous transmission. Trypanosoma cruzi DNA was detected by conventional polymerase chain reaction in Triatoma rubida captured at her home.

Notes from the Field: Fatal Pneumonic Tularemia Associated with Dog Exposure — Arizona, June 2016

On June 15, 2016, Arizona public health officials were notified of a presumptive positive Francisella tularensis blood culture result from a woman aged 73 years with pulmonary sarcoidosis who had recently died from respiratory failure. She had been taking amoxicillin for a dental infection. She was evaluated on June 6 for 4 days of fever, myalgia, anorexia, and diarrhea. Because of suspected colitis she was advised to discontinue amoxicillin; she declined hospital admission. Two days later, she was hospitalized for shortness of breath and confusion. Chest radiography revealed a right lower lobe pneumonia and an effusion. This was treated with cefepime and intravenous doxycycline. On June 8, her stool tested positive for Clostridium difficile toxin A/B by polymerase chain reaction, requiring treatment with metronidazole and vancomycin. Her condition deteriorated, and she died on June 11. Tularemia was not suspected as cause of illness until June 17 when a blood culture collected on June 6 was confirmed as F. tularensis, a Tier 1 select agent; no laboratory exposures occurred. The patient lived in a semirural area of northern Arizona, did not engage in outdoor activities, and had no known history of insect bites, exposure to animal carcasses or untreated water. She traveled to Hawaii May 16–26, returning approximately 11 days before illness onset. Postmortem exam revealed no bites, abscesses, or lymphadenopathy. The patient’s dog was noted to be lethargic and anorexic in late May, 3 days after being found with a rabbit carcass in its mouth. The patient and dog had frequent close contact. Serum from the dog, obtained approximately 3 weeks after its illness and the patient’s death, had a F. tularensis-specific titer of 1:256. An assessment of the property on June 23 revealed numerous rabbits and one squirrel carcass with F. tularensis DNA detected in its liver and spleen. Genotyping of F. tularensis from squirrel and human samples showed both infections were attributable to an A.II strain. Approximately 125 human tularemia cases are reported in the United States annually. Humans are infected through arthropod bites, contact with infectious tissues, inhalation, or ingestion (1). Symptoms commonly begin 3–5 days after exposure and can include fever, skin lesions, lymphadenopathy, difficulty breathing, and diarrhea (1). Two F. tularensis subspecies, tularensis (Type A) and holarctica (Type B), cause human tularemia (1,2). Distinct clades within Type A (A.I and A.II) are associated with different virulence in humans and laboratory animals (2,3). A.II strains are localized to the western United States and associated with milder illness than are A.I strains (2,3). Based on the patient’s respiratory symptoms, radiographic findings, and lack of alternative exposure history, exposure likely occurred at her property through inhalation of F. tularensis, potentially via close contact with her dog. The dog might have transmitted infectious material through oral secretions after mouthing an infected carcass or brought infectious material on its fur into contact with the patient. Human illness linked to dogs has been documented (3). The role of pulmonary sarcoidosis in this patient’s illness is unclear, but it might have contributed to the severe outcome of infection with an A.II strain (4). Concurrent infection with C. difficile might also have exacerbated the clinical course of tularemia. Diagnosis of tularemia is challenging because symptoms are nonspecific and exposure history is often unclear. Thorough ascertainment of animal exposures, including nature of contact, might refine clinical suspicion for specific zoonoses. Preventing exposure and implementing early, appropriate therapy can reduce morbidity and mortality. Additional information is available at https://www.cdc.gov/tularemia.