Soft Tick Relapsing Fever - United States, 2012-2021.

Soft tick relapsing fever (STRF) (also known as tickborne relapsing fever) is a rare infection caused by certain Borrelia spirochetes and transmitted to humans by soft-bodied Ornithodoros ticks. In the United States, acquisition of STRF is commonly associated with exposure to rustic cabins, camping, and caves. Antibiotic treatment is highly effective for STRF, but without timely treatment, STRF can result in severe complications, including death. No nationally standardized case definition for STRF exists; however, the disease is reportable in 12 states. This report summarizes demographic and clinical information for STRF cases reported during 2012-2021 from states where STRF is reportable. During this period, 251 cases were identified in 11 states. The median annual case count was 24. Most patients with STRF (55%) were hospitalized; no fatalities were reported. The geographic distribution and seasonal pattern of STRF have remained relatively constant since the 1990s. Persons should avoid rodent-infested structures and rodent habitats, such as caves, in areas where STRF is endemic. STRF surveillance, prevention, and control efforts would benefit from a standardized case definition and increased awareness of the disease among the public and clinicians.

The epidemiology of human ehrlichiosis in Texas, 2008-2017.

Tick-borne diseases in the United States, including ehrlichiosis, represent a growing public health problem. The purpose of this study was to examine the contemporary epidemiology of human ehrlichiosis in Texas by analyzing cases reported to the Texas Department of State Health Services. In Texas, 101 cases of ehrlichiosis were reported during 2008-2017. We observed geographic grouping of cases as well as an increasing trend of reported cases occurring annually from 2009 to 2017. Notably, 27 cases occurred in 2008 in south Texas with unique patient characteristics in that they were younger, less likely to be hospitalized, and presented with disease earlier in the year than typically seen. Our findings highlight the importance of disease awareness and prevention of tick bites as well as further investigation into transmission risk and future disease patterns.

Acute and Delayed Deaths after West Nile Virus Infection, Texas, USA, 2002-2012.

Infection with West Nile virus (WNV) has a well-characterized acute disease process. However, long-term consequences are less understood. We searched death records for 4,142 residents of Texas, USA, infected with WNV during 2002-2012 and identified 557 (13%) deaths. We analyzed all-cause and cause-specific deaths after WNV infection by calculating standardized mortality ratios and using statewide mortality data. Acute-phase deaths (<90 days after symptom onset) occurred in 289 (7%) of case-patients; of those deaths, 289 (92%) were cases of West Nile neuroinvasive disease (WNND). Convalescent-phase deaths (>90 days after symptom onset) occurred in 268 (7%) of the remaining 3,853 case-patients; 210 (78%) of these deaths occurred in patients with WNND. Convalescent-phase WNND case-patients showed excess deaths from infectious and renal causes; case-patients <60 years of age had increased risk for all-cause death, specifically from renal, infectious, digestive, and circulatory causes. We provide population-level evidence of increased risk for death after WNV infection resulting in WNND.

Chagas Disease Surveillance Activities - Seven States, 2017.

Chagas disease, a potentially life-threatening disease caused by the protozoan parasite Trypanosoma cruzi, has become a concern in the United States as a result of human emigration from Latin America where Chagas disease is endemic (1). It is estimated that as many as 8 million people living in Mexico, and Central and South America have Chagas disease.* Most cases of Chagas disease in the United States are chronic infections; however, rare cases of acute congenital infections and autochthonous vectorborne transmission have been reported (2). To understand how data are collected and used, a review of state-level public health surveillance for Chagas disease was conducted through semistructured interviews with health officials in six states (Arizona, Arkansas, Louisiana, Mississippi Tennessee, and Texas) where Chagas disease is reportable and one (Massachusetts) where it was previously reportable. States implemented surveillance in response to blood donor screening for Chagas disease and to identify the route of disease transmission. Many states reported primarily chronic cases and had limited ability to respond to local transmission because acute cases were infrequently reported. Surveillance remains important in states with large populations of immigrants or frequent travelers from countries with endemic disease and for states with a risk for local transmission. Surveillance efforts can also help increase awareness among providers and assist in linking patients with Chagas disease to treatment to help prevent cardiac and gastrointestinal complications.

PREVALENCE AND INTENSITY OF THE SINUS ROUNDWORM ( SKRJABINGYLUS CHITWOODORUM) IN RABIES-NEGATIVE SKUNKS OF TEXAS, USA.

: Estimates of the distribution and prevalence of the sinus roundworm ( Skrjabingylus chitwoodorum) have been based largely on the inspection of skunk (Mephitidae) skulls showing damage from infections. We examined 595 striped skunks ( Mephitis mephitis) and nine hog-nosed skunks ( Conepatus leuconotus) that had tested negative for rabies by the Texas Department of State Health Services (US) between November 2010 and April 2015 to determine species of Skrjabingylus, prevalence and intensity of infection, and distribution of infection in Texas by county. We expected ecoregions with more precipitation to have higher rates of infection than more-arid ecoregions. Prevalence of S. chitwoodorum in striped skunks was 48.7%, with a mean intensity of 19.4 (SD=24.44, range=1-181) nematodes. There was a bias for the left sinus. The prevalence of infection varied among ecoregions of Texas, but it was not correlated with precipitation. Infection intensity did not vary among ecoregions. The prevalence of sinus roundworms in rabies-negative skunks suggested that behavioral changes because of skrjabingylosis might have been responsible for the submission by the public of some skunks for rabies testing.

Fatal Flea-Borne Typhus in Texas: A Retrospective Case Series, 1985-2015.

AbstractFlea-borne (murine) typhus is a global rickettsiosis caused by Rickettsia typhi. Although flea-borne typhus is no longer nationally notifiable, cases are reported for surveillance purposes in a few U.S. states. The infection is typically self-limiting, but may be severe or life-threatening in some patients. We performed a retrospective review of confirmed or probable cases of fatal flea-borne typhus reported to the Texas Department of State Health Services during 1985-2015. When available, medical charts were also examined. Eleven cases of fatal flea-borne typhus were identified. The median patient age was 62 years (range, 36-84 years) and 8 (73%) were male. Patients presented most commonly with fever (100%), nausea and vomiting (55%), and rash (55%). Respiratory (55%) and neurologic (45%) manifestations were also identified frequently. Laboratory abnormalities included thrombocytopenia (82%) and elevated hepatic transaminases (63%). Flea or animal contact before illness onset was frequently reported (55%). The median time from hospitalization to administration of a tetracycline-class drug was 4 days (range, 0-5 days). The median time from symptom onset to death was 14 days (range, 1-34 days). Flea-borne typhus can be a life-threatening disease if not treated in a timely manner with appropriate tetracycline-class antibiotics. Flea-borne typhus should be considered in febrile patients with animal or flea exposure and respiratory or neurologic symptoms of unknown etiology.

Typhus Group Rickettsiosis, Texas, USA, 2003-2013.

We characterized the epidemiology of typhus group rickettsiosis in Texas, USA. During 2003-2013, a total of 1,762 cases were reported to the state health department. The number of diagnosed cases and geographic expansion increased over time. Physician awareness is critical to diagnose and effectively treat rickettsial infections.

Trypanosome species, including Trypanosoma cruzi, in sylvatic and peridomestic bats of Texas, USA.

In contrast to other mammalian reservoirs, many bat species migrate long-distances and have the potential to introduce exotic pathogens to new areas. Bats have long been associated with blood-borne protozoal trypanosomes of the Schizotrypanum subgenus, which includes the zoonotic parasite Trypanosoma cruzi, agent of Chagas disease. Another member of the subgenus, Trypanosoma dionisii, infects bats of Europe and South America, and genetic similarities between strains from the two continents suggest transcontinental movement of this parasite via bats. Despite the known presence of diverse trypanosomes in bats of Central and South America, and the presence of T. cruzi-infected vectors and wildlife in the US, the role of bats in maintaining and dispersing trypanosomes in the US has not yet been reported. We collected hearts and blood from 8 species of insectivorous bats from 30 counties across Texas. Using PCR and DNA sequencing, we tested 593 bats for trypanosomes and found 1 bat positive for T. cruzi (0.17%), 9 for T. dionisii (1.5%), and 5 for Blastocrithidia spp. (0.8%), a group of insect trypanosomes. The T. cruzi-infected bat was carrying TcI, the strain type associated with human disease in the US. In the T. dionisii-infected bats, we detected three unique variants associated with the three infected bat species. These findings represent the first report of T. cruzi in a bat in the US, of T. dionisii in North America, and of Blastocrithidia spp. in mammals, and underscore the importance of bats in the maintenance of trypanosomes, including agents of human and animal disease, across broad geographic locales.

The phylogeography and spatiotemporal spread of south-central skunk rabies virus.

The south-central skunk rabies virus (SCSK) is the most broadly distributed terrestrial viral lineage in North America. Skunk rabies has not been efficiently targeted by oral vaccination campaigns and represents a natural system of pathogen invasion, yielding insights to rabies emergence. In the present study we reconstructed spatiotemporal spread of SCSK in the whole territory of its circulation using a combination of Bayesian methods. The analysis based on 241 glycoprotein gene sequences demonstrated that SCSK is much more divergent phylogenetically than was appreciated previously. According to our analyses the SCSK originated in the territory of Texas ~170 years ago, and spread geographically during the following decades. The wavefront velocity in the northward direction was significantly greater than in the eastward and westward directions. Rivers (except the Mississippi River and Rio Grande River) did not constitute significant barriers for epizootic spread, in contrast to deserts and mountains. The mean dispersal rate of skunk rabies was lower than that of the raccoon and fox rabies. Viral lineages circulate in their areas with limited evidence of geographic spread during decades. However, spatiotemporal reconstruction shows that after a long period of stability the dispersal rate and wavefront velocity of SCSK are increasing. Our results indicate that there is a need to develop control measures for SCSK, and suggest how such measure can be implemented most efficiently. Our approach can be extrapolated to other rabies reservoirs and used as a tool for investigation of epizootic patterns and planning interventions towards disease elimination.

Epidemiology of rabies in bats in Texas (2001-2010).

OBJECTIVE: To obtain epidemiological information on rabies in bats in Texas. DESIGN: Epidemiological study. SAMPLE: Laboratory reports of bats that had been submitted for rabies testing in Texas from 2001 through 2010. PROCEDURES: Laboratory reports were reviewed to obtain information on seasonality of rabies in bats; distribution, species, and rabies virus variants of rabid bats; and human and domestic animal exposures to rabid bats. RESULTS: The number of rabid bats during the first 5 years of the study period remained static until a > 2-fold increase in 2006; during the subsequent 4 years, the annual number of rabid bats remained at this higher level, including a peak in 2008. The highest proportions of rabid bats were seen in late summer and early fall. The Brazilian free-tailed bat (Tadarida brasiliensis) was the most often affected species. Additionally, the rabies virus variant associated with the Brazilian free-tailed bat was the most prevalent. The percentage of rabid bats from urban areas was greater than that from rural areas. Dogs and cats were the domestic animals most frequently exposed to rabid bats. Most humans exposed to rabid bats did not report a known bite or scratch. The highest numbers of humans exposed to rabid bats were males between 11 to 15 years old. CONCLUSIONS AND CLINICAL RELEVANCE: Information on the epidemiology of rabies in bats and the epidemiology of exposures to rabid bats may be useful in planning and implementing local, state, and national rabies control and prevention campaigns and in encouraging rabies vaccination of domestic animals.

Bat rabies, Texas, 1996-2000.

Bats submitted to the Texas Department of Health (1996-2000) were speciated and tested for rabies virus antigen by direct immunofluorescence microscopy. Antigenic analysis of rabies virus-positive specimens was performed with monoclonal antibodies against the nucleoprotein of the virus; atypical or unexpected results were confirmed by genetic analysis of nucleoprotein sequence.