Saithip Bhengsri

Identification of Bartonella Infections in Febrile Human Patients from Thailand and Their Potential Animal Reservoirs

To determine the role of Bartonella species as causes of acute febrile illness in humans from Thailand, we used a novel strategy of co-cultivation of blood with eukaryotic cells and subsequent phylogenetic analysis of Bartonella-specific DNA products. Bartonella species were identified in 14 blood clots from febrile patients. Sequence analysis showed that more than one-half of the genotypes identified in human patients were similar or identical to homologous sequences identified in rodents from Asia and were closely related to B. elizabethae, B. rattimassiliensis, and B. tribocorum. The remaining genotypes belonged to B. henselae, B. vinsonii, and B. tamiae. Among the positive febrile patients, animal exposure was common: 36% reported owning either dogs or cats and 71% reported rat exposure during the 2 weeks before illness onset. The findings suggest that rodents are likely reservoirs for a substantial portion of cases of human Bartonella infections in Thailand.

Melioidosis Diagnostic Workshop, 20131

Melioidosis is a severe disease that can be difficult to diagnose because of its diverse clinical manifestations and a lack of adequate diagnostic capabilities for suspected cases. There is broad interest in improving detection and diagnosis of this disease not only in melioidosis-endemic regions but also outside these regions because melioidosis may be underreported and poses a potential bioterrorism challenge for public health authorities. Therefore, a workshop of academic, government, and private sector personnel from around the world was convened to discuss the current state of melioidosis diagnostics, diagnostic needs, and future directions.

Bartonella vinsonii subsp. arupensis in Humans, Thailand

We identified Bartonella vinsonii subsp. arupensis in pre-enriched blood of 4 patients from Thailand. Nucleotide sequences for transfer-messenger RNA gene, citrate synthase gene, and the 16S–23S rRNA internal transcribed spacer were identical or closely related to those for the strain that has been considered pathogenic since initially isolated from a human in Wyoming, USA.

Infective Endocarditis in Northeastern Thailand

Despite rigorous diagnostic testing, the cause of infective endocarditis was identified for just 60 (45.5%) of 132 patients admitted to hospitals in Khon Kaen, Thailand, during January 2010–July 2012. Most pathogens identified were Viridans streptococci and zoonotic bacteria species, as found in other resource-limited countries where underlying rheumatic heart disease is common.

Rabies-Related Knowledge and Practices Among Persons At Risk of Bat Exposures in Thailand

Background Rabies is a fatal encephalitis caused by lyssaviruses. Evidence of lyssavirus circulation has recently emerged in Southeast Asian bats. A cross-sectional study was conducted in Thailand to assess rabies-related knowledge and practices among persons regularly exposed to bats and bat habitats. The objectives were to identify deficiencies in rabies awareness, describe the occurrence of bat exposures, and explore factors associated with transdermal bat exposures. Methods A survey was administered to a convenience sample of adult guano miners, bat hunters, game wardens, and residents/personnel at Buddhist temples where mass bat roosting occurs. The questionnaire elicited information on demographics, experience with bat exposures, and rabies knowledge. Participants were also asked to describe actions they would take in response to a bat bite as well as actions for a bite from a potentially rabid animal. Bivariate analysis was used to compare responses between groups and multivariable logistic regression was used to explore factors independently associated with being bitten or scratched by a bat. Findings Of 106 people interviewed, 11 (10%) identified bats as a potential source of rabies. A history of a bat bite or scratch was reported by 29 (27%), and 38 (36%) stated either that they would do nothing or that they did not know what they would do in response to a bat bite. Guano miners were less likely than other groups to indicate animal bites as a mechanism of rabies transmission (68% vs. 90%, p = 0.03) and were less likely to say they would respond appropriately to a bat bite or scratch (61% vs. 27%, p = 0.003). Guano mining, bat hunting, and being in a bat cave or roost area more than 5 times a year were associated with history of a bat bite or scratch. Conclusions These findings indicate the need for educational outreach to raise awareness of bat rabies, promote exposure prevention, and ensure appropriate health-seeking behaviors for bat-inflicted wounds, particularly among at-risk groups in Thailand.

Incidence of Bacteremic Melioidosis in Eastern and Northeastern Thailand

Burkholderia pseudomallei, the causative agent of melioidosis, is endemic in northeastern Thailand. Population-based disease burden estimates are lacking and limited data on melioidosis exist from other regions of the country. Using active, population-based surveillance, we measured the incidence of bacteremic melioidosis in the provinces of Sa Kaeo (eastern Thailand) and Nakhon Phanom (northeastern Thailand) during 2006-2008. The average annual incidence in Sa Kaeo and Nakhon Phanom per 100,000 persons was 4.9 (95% confidence interval [CI] = 3.9-6.1) and 14.9 (95% CI = 13.3-16.6). The respective population mortality rates were 1.9 (95% CI = 1.3-2.8) and 4.4 (95% CI = 3.6-5.3) per 100,000. The case-fatality proportion was 36% among those with known outcome. Our findings document a high incidence and case fatality proportion of bacteremic melioidosis in Thailand, including a region not traditionally considered highly endemic, and have potential implications for clinical management and health policy.

Bartonella spp. Infections, Thailand

To the Editor: Bartonella are fastidious hemotropic gram-negative bacteria with a worldwide distribution. In Thailand, Bartonella species have been demonstrated in mammalian hosts, including rodents, cats and dogs, and in potential vectors, including fleas (1–4). However, data on human infection have been limited to case reports (5,6) and 1 seroprevalence survey, which found a 5.5% prevalence of past B. henselae infection (7). No studies have systematically assessed the frequency, clinical characteristics, or epidemiology of human Bartonella infections in Thailand. We conducted a prospective study to determine causes of acute febrile illness in 4 community hospitals, 2 in Chiang Rai (northern Thailand) and 2 in Khon Kaen (northeastern Thailand). We enrolled patients >7 years of age with a temperature >38°C who were brought to study hospitals for treatment from February 4, 2002, through March 28, 2003. Patients were excluded if they had a history of fever for >2 weeks or an infection that could be diagnosed clinically. Acute-phase serum samples were collected at the time of enrollment and convalescent-phase serum samples 3–5 weeks later. We enrolled nonfebrile control patients >14 years of age who had noninfectious conditions; acute-phase serum samples were collected. Clinical information was abstracted from patient charts. Nurses conducted physical examinations and personal interviews to collect information on patients’ demographic characteristics, exposures to animals, and outdoor activities. Serum samples were tested for immunoglobulin (Ig) G antibodies to Bartonella spp. by immunofluorescent antibody assay at the Bartonella Laboratory of the Centers for Disease Control and Prevention, Fort Collins, CO, USA. Strains used for antigen production were: B. elizabethae (F9251), B. henselae (Houston-1), B. quintana (Fuller), and B. vinsonii subsp. vinsonii (Baker). Homologous hyperimmune serum specimens were produced in BALB/c mice as previously described (8). Bartonella infection was considered confirmed in febrile patients who had a >4-fold rise in IgG antibody titers and a convalescent-phase titer >64. Probable infection was defined as 1) a 4-fold antibody titer rise but convalescent-phase titers of 64, or 2) high and stable titers (>512 in acute-phase and convalescent-phase serum samples), or 3) acute-phase titer >512 with a >4-fold titer fall. Paired serum samples from febrile patients were also tested for serologic evidence of other common causes of febrile illness in Southeast Asia. Febrile patients with acute-phase and convalescent-phase IgG antibody titers 14 years of age without serologic evidence of other infections (n = 20) to nonfebrile controls with IgG to Bartonella <128 (n = 70). Age adjusted odds ratios (AORs) with 95% confidence intervals (CIs) were calculated. Serologic testing was completed on paired serum samples for 336 (46%) of 732 febrile patients enrolled; 92 (27%) had serologically confirmed (50) or probable (42) Bartonella infections. Thirty-five (38%) of these 92 had serologic evidence of infection with another pathogen. The remaining 57 Bartonella-infected case-patients (34 confirmed, 23 probable) had a median age of 19 years (range 7–72 years); 65% were males, 47% were students, and 35% were rice farmers. Common clinical characteristics of Bartonella-infected patients included myalgias (83%), chills (79%), and headache (77%). Thirty (60%) patients had anemia (hemoglobin level <13 mg/dL); 18 (32%) had a hemoglobin level <12 mg/dL, and 4 (7%) had <11 mg/dL. When compared with 193 febrile patients without Bartonella infection, the 57 Bartonella-infected patients were similar in age and sex but were more likely to be rice farmers and were more likely to have leukocytosis (Table). Compared with the 70 nonfebrile controls, Bartonella-infected case-patients were more likely to report tick exposure (32% vs. 7.9%; AOR = 5.6, 95% CI 1.5–21) and outdoor activities (55% vs. 31%; AOR = 2.7, 95% CI 1.0–7.4) during the 2 weeks before illness onset. Prevalence of reported rat exposure and animal ownership (cats, dogs, pigs, cows, or buffaloes) was similar among case-patients and controls. Table Demographic and clinical characteristics of febrile patients with Bartonella infection compared with febrile patients who had no evidence of Bartonella infection, Thailand, 2002–2003* We describe the frequency and clinical characteristics of acute Bartonella infection among febrile patients in Thailand. Over 25% of patients with undifferentiated febrile illness had serologic evidence of Bartonella infection (including 15% serologically confirmed). Our findings indicate that Bartonella infections may be common and underrecognized causes of acute febrile illness in rural Thailand. Although our results are limited by lack of culture confirmation, we used conservative case definitions for serologic diagnosis and therefore believe that most cases represent true Bartonella infections. The common clinical features of anemia and leukocytosis and the frequent tick exposure and outdoor activity are consistent with known features of Bartonella infections and lend support to serologic findings. Because of the potential for serologic cross-reactivity between Bartonella species, we did not attempt species identification. The case-control study was therefore limited by grouping case-patients that were likely infected with different Bartonella species for which risk factors may differ. Such studies could lead to meaningful recommendations for prevention and control of Bartonella infections. Additional epidemiologic and transmission studies are needed to improve understanding of risk factors, identify key animal reservoirs and vectors, and ascertain transmission dynamics.

Economic burden of bacteremic melioidosis in eastern and northeastern, Thailand.

Melioidosis is among the most common causes of septicemia in Thailand, but data on economic burden are limited. We describe the economic impact of bacteremic melioidosis hospitalizations in two Thailand provinces during 2006-2008. Costs are presented in US dollars (

Sennetsu Neorickettsiosis, Spotted Fever Group, and Typhus Group Rickettsioses in Three Provinces in Thailand

1 = 30.49 Thai Baht). The average annual incidence of bacteremic melioidosis cases per 100,000 persons in Sa Kaeo and Nakhon Phanom was 4.6 and 14.4, respectively. The annual cost of bacteremic melioidosis hospitalizations from the societal perspective, including direct and indirect costs, was

Acute Q Fever Case Detection among Acute Febrile Illness Patients, Thailand, 2002–2005

152,159 in Sa Kaeo and