The Epidemiology and Characteristics of Q fever and Co-infections with Scrub Typhus, Murine Typhus or Leptospirosis in Taiwan: A Nationwide Database Study

Identification and distribution of pathogens coinfecting with Brucella spp., Coxiella burnetii and Rift Valley fever virus in humans, livestock and wildlife

Zoonotic diseases, such as brucellosis, Q fever and Rift Valley fever (RVF) caused by Brucella spp., Coxiella burnetii and RVF virus, respectively, can have devastating effects on human, livestock, and wildlife health and cause economic hardship due to morbidity and mortality in livestock. Coinfection with multiple pathogens can lead to more severe disease outcomes and altered transmission dynamics. These three pathogens can alter host immune responses likely leading to increased morbidity, mortality and pathogen transmission during coinfection. Developing countries, such as those commonly afflicted by outbreaks of brucellosis, Q fever and RVF, have high disease burden and thus common coinfections. A literature survey provided information on case reports and studies investigating coinfections involving the three focal diseases. Fifty five studies were collected demonstrating coinfections of Brucella spp., C. burnetii or RVFV with 50 different pathogens, of which 64% were zoonotic. While the literature search criteria involved ‘coinfection’, only 24/55 studies showed coinfections with direct pathogen detection methods (microbiology, PCR and antigen test), while the rest only reported detection of antibodies against multiple pathogens, which only indicate a history of co‐exposure, not concurrent infection. These studies lack the ability to test whether coinfection leads to changes in morbidity, mortality or transmission dynamics. We describe considerations and methods for identifying ongoing coinfections to address this critical blind spot in disease risk management.

Epidemiology and risk factors of scrub typhus in Taiwan: A nationwide database study from 1996 to 2014

BACKGROUND

Scrub typhus (ST) is one of the most underdiagnosed, potentially fatal febrile diseases in the Asia-Pacific region. We conducted a comprehensive review of the risk factors of ST over 19 years using data from a nationwide database.

METHODS

We used data on ST from the nationwide database of the Taiwan Centers for Disease Control from 1996 to 2014 to analyse the incidence rates and relative risks of ST according to different regions. The trends of incidence rates over the study period were also evaluated. The distribution of confirmed ST cases was mapped using geographic information system software. The characteristics of confirmed ST cases and non-ST cases (cases with suspected ST but negative test findings) were compared.

RESULTS

Among the 38,127 reported cases, there were 6,791 (17.8%) confirmed ST cases. The overall incidence rate of ST in Taiwan was 1.49 per 100,000 residents per year. The trend of incidence rates increased over time. The Island region had the highest incidence rate (56.55 per 100,000 residents per year), followed by the Eastern region (15.13 per 100,000 residents per year). More confirmed ST cases were distributed in mountainous areas of Taiwan Main Island and Island region. Compared to non-ST cases, individuals with confirmed ST were younger (median [interquartile range] age: 44 [26-57] years versus 45 [30-60] years, p < .001) and more likely to engage in at-risk occupations (29.4% versus 13.3%, p < .001), including farming and animal husbandry (16.6% versus 9.0%, p < .001) and the armed forces (12.3% versus 3.5%, p < .001); however, they had a lower rate of animal contact (12.8% versus 20.1%, p < .001).

CONCLUSIONS

ST is an endemic disease in Taiwan, particularly in the Island region, Eastern region and mountainous areas. Patients engaged in at-risk occupations and presenting with acute febrile diseases should undergo investigations for ST.

Leptospirosis and Rickettsial Diseases Sero-Conversion Surveillance Among U.S. Military Personnel in Honduras

INTRODUCTION

Leptospirosis and rickettsial diseases are global zoonotic diseases. In severe infection cases, mortality can range from 10% to 30%. Currently most epidemiological data available are based on outbreak investigations and hospital-based studies from endemic countries. The U.S. soldiers at military bases in these countries are highly vulnerable due to the fact that most of them are immunologically naïve to these pathogens. No risk assessment of leptospirosis and rickettsial diseases among U.S. military personnel in Honduras is currently available. This study was aimed at determining the prevalence of leptospirosis and rickettsial diseases in U.S. military personnel deployed to Honduras using serological assays.

MATERIALS AND METHODS

A cohort of pre- and post-deployment sera from the most recent 1,000 military personnel stationed in Honduras for at least 6 months between 2000 and 2016 was identified for this study. Serum specimens from these eligible subjects were retrieved. All post-deployment serum specimens were screened at a dilution of 1:100 for the presence of IgG antibodies to Leptospira and Rickettsia pathogens. The pre-deployment sera from those individuals with post-deployment IgG antibodies above cutoff (i.e., seropositive) were tested to determine seroconversion. Seroconversion was defined as conversion of an optical density value from below the cutoff (i.e., negative) in a pre-deployed specimen to above the cutoff (i.e., positive) in a post-deployed specimen at a titer of 100.

RESULTS

The seropositive post-deployment specimens for antibodies against Leptospira (causing leptospirosis), Rickettsia typhi (causing murine typhus [MT]), spotted fever group rickettsioses (SFGR, causing SFG Rickettsia), Orientia tsutsugamushi (causing scrub typhus [ST]), and Coxiella burnetii (causing Q fever [QF]) were 11.6%, 11.3%, 6%, 5.6%, and 8.0%, respectively. The seroconverted rate in those assigned to Honduras from 2000 to 2016 was 7.3%, 1.9%, 3.9%, 4.3%, and 2.7% for leptospirosis, MT, SFGR, ST, and QF, respectively. Among the seroconverted specimens, 27 showed seroconversion of at least two antibodies. These seroconverted individuals accounted for 8.8% (3 out of 34) of the personnel who looked for medical attention during their deployment.

CONCLUSIONS

Our results suggest a leptospirosis seroconversion rate of 7.3%, which is higher than the 0.9% and 3.9% seroconversion in Korea and Japan, respectively. The higher rate of seroconversion indicates potential risk of Leptospira exposure. Additional testing of water samples in the pools and pits around the training sites to locate the infected areas is important to eliminate or reduce future exposure to Leptospira during trainings. The rates of seroconversion for ST, MT, spotted fever Rickettsia, and QF were 4.3%, 1.9%, 3.9%, and 2.7%, respectively, indicating the potential exposure to a variety of rickettsial-related pathogens. Testing of vectors for rickettsial pathogens in the areas could inform effective vector control countermeasures to prevent exposure. Proper precaution and protective measures are needed to better protect military personnel deployed to Honduras.

Selection of Diagnostic Cutoffs for Murine Typhus IgM and IgG Immunofluorescence Assay: A Systematic Review

Murine typhus is a neglected but widespread infectious disease that results in acute fever. The immunofluorescence assay (IFA) is the "gold standard" to identify IgM or IgG antibodies, although there is a lack of standardization in methodologies. The objective of this review is to summarize 1) the differences in published methodologies, 2) the diagnostic cutoff titers, and 3) the justification of diagnostic cutoffs. Searches were performed by combining the following search terms: "murine typhus," "rickettsia typhi," "immunofluorescence," "IFA," and "serologic" with restrictions (i.e., "rickettsia typhi" or "murine typhus," and "IFA" or "immunofluorescence," or "serologic*"). The search identified 78 studies that used IFA or immunoperoxidase assay (IIP) antibody cutoffs to diagnose murine typhus, 39 of which were case series. Overall, 45 studies (57.7%) provided little to no rationale as to how the cutoff was derived. Variation was seen locally in the cutoff titers used, but a 4-fold or greater increase was often applied. The cutoffs varied depending on the antibody target. No consensus was observed in establishing a cutoff, or for a single-value diagnostic cutoff. In conclusion, there is a lack of consensus in the establishment of a single-value cutoff. Further studies will need to be executed at each distinct geographic location to identify region-specific cutoffs, while also considering background antibody levels to distinguish between healthy and infected patients.

Serum C-reactive protein and procalcitonin values in acute Q fever, scrub typhus, and murine typhus

Background

Although C-reactive protein (CRP) and procalcitonin (PCT) are widely used inflammatory markers for infectious diseases, their role and potential application for rickettsioses were rarely studied.

Methods

A retrospective chart review and serological study were conducted in patients with rickettsioses. The clinical presentations, characteristics, laboratory data, and treatment responses were recorded and their associations with CRP and PCT values were analyzed.

Results

A total of 189 cases of rickettsioses, including 115 cases of acute Q fever (60.8%), 55 cases of scrub typhus (29.1%), and 19 cases of murine typhus (10.1%) were investigated. Both CRP and PCT values increased in the acute phase and declined in the convalescent phase. In the acute phase, mean CRP and PCT values were 78.2 ± 63.7 mg/L and 1.05 ± 1.40 ng/mL, respectively. Percentages of patients falling under different cut-off values of CRP and PCT were calculated systematically. Only 10.8% of CRP was > 150 mg/L and 14.2% of PCT was > 2.0 ng/mL. Patients with delayed responses to doxycycline treatment (> 3 days from treatment to defervescence) had significantly higher CRP values (102.7 ± 77.1 vs. 72.2 ± 58.2 mg/L, p = 0.041) and more PCT > 1.0 ng/ml (48.4% vs. 26.0%, p = 0.019) in the acute phase; higher CRP values (19.1 ± 37.4 vs. 3.6 ± 13.1 mg/L, p = 0.049) and more PCT > 0.5 ng/ml (19.2% vs. 1.4%, p = 0.005) in the convalescent phase. Correlation analysis was conducted for patients with acute Q fever. CRP and PCT values were positively correlated to each other, and both markers also had a positive correlation with serum aspartate transaminase values. Both CRP and PCT values and white blood cell counts were positively correlated to the days needed from doxycycline treatment to defervescence.

Conclusion

CRP and PCT values might be useful in clinical investigations for patients with suspected rickettsioses and in predicting the response to doxycycline treatment for rickettsioses.

Leptospirosis trends in China, 2007-2018: A retrospective observational study

Leptospirosis is one of the most common and neglected tropical waterborne diseases in China, causing serious economic losses, and constituting a significant public health threat. Leptospirosis has recently received increased attention and is considered a re-emerging infectious disease in many countries. The incidence of leptospirosis among people suggests that occupation, age, season, sex and water recreational activities are significant risk factors. The aim of this study was to describe the epidemiological profiles of leptospirosis in China during the 2007-2018 period. The morbidity data of leptospirosis by age, season (month), gender, occupation and geographic location (different provinces) were obtained from the public health science data centre of China for subsequent epidemiological analysis. The results indicate that the incidence of leptospirosis has shown a slow downward trend from 2007 to 2018, but morbidity rates were still relatively high (0.0660-0.0113). The incidence of leptospirosis varied in different provinces of China; cases localized mainly to the Southern and Central provinces, areas with warm weather and ample rainfall. Older people (aged 60-75), males, farmers, students and field workers were high-risk populations. During the 2007-2018 observation period, morbidity rates increased beginning in May, remained at high levels in August and September and decreased after November. The present investigation highlights the re-emergence of leptospirosis in some provinces of China (especially in Yunnan and Fujian) and shows that leptospirosis remains a serious public health threat. The results of this study should enhance measures taken for the prevention, control, and surveillance of leptospirosis in China.

The epidemiology, characteristics and outbreaks of human leptospirosis and the association with animals in Taiwan, 2007-2014: A nationwide database study

BACKGROUND

Leptospirosis (LS) is a neglected tropical zoonosis of global importance. A nationwide investigation of characteristics, epidemiology, risk factors and outbreak is crucial for awareness of this disease.

METHODS

A nationwide database of reported LS cases from October 2007 to December 2014 obtained from the Centers for Disease Control, Taiwan, was analysed. Geographic information system software was used to map the distribution of confirmed LS cases and pigs. Cross-matching with the databases of Q fever, scrub typhus and murine typhus was conducted to identify possible coinfections.

RESULTS

A total of 10,917 reported cases of LS were recorded in the database, which included 665 (6.1%) confirmed LS and 10,252 (93.9%) non-confirmed LS cases. The major residences of confirmed LS were the Kaohsiung-Pingtung (248, 37.3%) and Taipei (174, 26.2%) regions. The average annual incidence was 0.4/100,000 people. Compared with non-confirmed LS cases, confirmed LS cases had significantly higher percentages of male gender (83.6% vs. 67.9%, p < .001), high-risk occupations (farmer, animal husbandry or veterinarian) (24.8% vs. 13.7%, p < .001), residence in the Kaohsiung-Pingtung region (37.3% vs. 19.6%, p < .001) and exposure to rats (8.6% vs. 4.9%, p = .001) or pigs (9.4% vs. 1.9%, p < .001) but a lower mean age (47.8 ± 15.1 vs. 51.±18.5 years old). Rat and pig exposure trends were found in the northern and southern regions, respectively. Distribution of LS was consistent with pigs, and one outbreak associated with flooding and pigs occurred in the Pingtung region in 2009. Twenty-three and four patients with LS were coinfected with scrub typhus and Q fever, respectively.

CONCLUSIONS

LS is an endemic disease in Taiwan, particularly in the Kaohsiung-Pingtung and Taipei regions. High-risk occupations and animal exposure history are important for the clinical presumptive diagnosis of LS, particularly for rats in northern Taiwan and pigs in southern Taiwan. Although uncommon, clinicians should be aware of coinfection of LS with endemic rickettsial diseases.

Spatial, temporal, and occupational risks of Q fever infection in South Australia, 2007-2017

BACKGROUND

The burden of Q fever on at risk population groups in Australia is substantial, despite the availability of a vaccine. Our objectives were to: (a) describe the epidemiology of notified Q fever cases in South Australia (SA), (b) identify if Q fever infection is associated with occupational exposure, and (c) detect the possible spatial and temporal association of Q fever with livestock density.

METHODS

Laboratory confirmed Q fever notifications from January 2007 to December 2017 were obtained from the SA Health Department. Q fever notification rates and incidence rate ratios were calculated for gender, notification year, age group, occupation category, and primary exposure suburb. Spatial mapping and analysis of Q fever notifications was undertaken using livestock data, and abattoirs and saleyards located in SA.

RESULTS

During the study period 167 Q fever cases were notified. Males predominated (72%), with higher rates observed in the 21-40year age group (1.52/100,000), and eight cases (5%) reported prior Q fever vaccination. Most frequently listed occupation categories were livestock farmers (35%), and abattoir workers (20%), but in 15% of cases, there was no known occupational risk. Highest notifications (22%) were recorded in the suburb containing an abattoir. The number of goats, cattle and sheep was not associated with Q fever notifications.

CONCLUSIONS

Q fever predominance among males in their twenties and thirties may indicate vaccination under-coverage among the young workforce possibly due to high turnover of workers. Q fever among those vaccinated raises concerns about vaccine efficacy or potential waning immunity. Our findings are consistent with previous studies highlighting abattoir workers as a high-risk occupational group because of its transient workforce, and low vaccination coverage. Q fever notifications in SA may be unrelated with spatial livestock density. Further One Health research involving veterinary, public health and environmental data is required.

Usefulness of the FilmArray meningitis/encephalitis (M/E) panel for the diagnosis of infectious meningitis and encephalitis in Taiwan

BACKGROUND/PURPOSE

Early recognition of causative pathogens is critical for the appropriate management of central nervous system infection and improved outcomes. The BioFire^® FilmArray^® Meningitis/Encephalitis Panel (BioFire^® ME Panel, BioFire Diagnostics) is the first U.S. Food and Drug Administration (FDA)-approved multiplex PCR assay that allows the rapid detection of 14 pathogens, including bacteria (n = 6), viruses (n = 7), and fungi (n = 1), from cerebrospinal fluid (CSF). The performance of the panel is expected to be dependent on the epidemiology of M/E in different geographical regions.

METHODS

In this preliminary study, we used the BioFire^® ME Panel in 42 subjects who presented to the emergency department with symptoms of M/E in our hospital. The results were compared to conventional culture, antigen detection, PCR, and various laboratory findings.

RESULTS

The panel detected six positive samples, of which five were viral and one bacterial. We observed an overall agreement rate of 88% between the BioFire^® ME Panel results and the conventional methods. There were no false-positive findings, but five discordant results were observed for enterovirus, herpes simplex virus type 1, Escherichia coli, and Cryptococcus species.

CONCLUSIONS

The BioFire^® ME Panel performed equivalently to the traditional PCR methods for virus detection, and better than bacterial cultures. This revolutionary system represents a paradigm shift in the diagnosis of M/E and may aid in the rapid identification of community-acquired M/E. However, the usefulness of this tool is limited in regions with a high prevalence of infectious M/E caused by microorganisms not included in the panel.

Clinicoepidemiologic characteristics of scrub typhus and murine typhus: A multi-center study in southern Taiwan

BACKGROUND

This study aimed to offer key features to differentiate scrub typhus (ST) and murine typhus (MT) at the early stage of the diseases and provide clinicoepidemiologic characteristics of ST and MT in southern Taiwan, a region where both diseases are endemic. Comparison of doxycycline treatment efficacy between the two diseases by matching disease severity and delayed treatment had never been investigated.

METHODS

We reviewed the medical records of cases of ST and MT in four hospitals in southern Taiwan. Propensity-score matching was used to analyze the defervescence curves between patients with doxycycline-treated ST and MT by log-rank test.

RESULTS

Between 2004 and 2016, 265 ST and 63 MT cases were diagnosed. The number of cases of ST was significantly related to temperature (Rs = 0.77) and rainfall (Rs = 0.63). Island area exposure, arthropod bite, eschar, and lymphadenopathy were only recorded in ST patients. Multivariate analysis revealed that mountainous area exposure (odds ratio [OR], 11.0; 95% confidence interval [CI], 4.4-27.2) was an independent predictor for ST, while contact with rats (OR, 8.4; 95% CI, 3.3-21.3) was that for MT. After propensity-score matching, there was no difference in defervescence curves between these two rickettsioses treated with doxycycline (p = 0.24).

CONCLUSION

In the present study, island area exposure, arthropod bite, eschar, and lymphadenopathy were unique manifestations of ST. Mountainous area exposure is a predictive factor for ST, while contact with rats predicted MT. There was no difference in defervescence time between these two rickettsioses after doxycycline treatment.

Is a One Health Approach Utilized for Q Fever Control? A Comprehensive Literature Review

Q fever, a zoonotic disease transmitted from animals to humans, is a significant public health problem with a potential for outbreaks to occur. Q fever prevention strategies should incorporate human, animal, and environmental domains. A One Health approach, which engages cross-sectoral collaboration among multiple stakeholders, may be an appropriate framework and has the underlying principles to control Q fever holistically. To assess whether components of One Health for Q fever prevention and control have been applied, a comprehensive literature review was undertaken. We found 16 studies that had practiced or recommended a One Health approach. Seven emerging themes were identified: Human risk assessment, human and animal serology, integrated human⁻animal surveillance, vaccination for at-risk groups, environmental management, multi-sectoral collaboration, and education and training. Within the multi-sectoral theme, we identified five subthemes: Policy and practice guidelines, information sharing and intelligence exchange, risk communication, joint intervention, and evaluation. One Health practices varied between studies possibly due to differences in intercountry policy, practice, and feasibility. However, the key issue of the need for multi-sectoral collaboration was highlighted across most of the studies. Further research is warranted to explore the barriers and opportunities of adopting a One Health approach in Q fever prevention and control.

The Re-Emergence and Emergence of Vector-Borne Rickettsioses in Taiwan

Rickettsial diseases, particularly vector-borne rickettsioses (VBR), have a long history in Taiwan, with studies on scrub typhus and murine typhus dating back over a century. The climatic and geographic diversity of Taiwan's main island and its offshore islands provide many ecological niches for the diversification and maintenance of rickettsiae alike. In recent decades, scrub typhus has re-emerged as the most prevalent type of rickettsiosis in Taiwan, particularly in eastern Taiwan and its offshore islands. While murine typhus has also re-emerged on Taiwan's western coast, it remains neglected. Perhaps more alarming than the re-emergence of these rickettsioses is the emergence of newly described VBR. The first case of human infection with Rickettsia felis was confirmed in 2005, and undetermined spotted fever group rickettsioses have recently been detected. Taiwan is at a unique advantage in terms of detecting and characterizing VBR, as it has universal health coverage and a national communicable disease surveillance system; however, these systems have not been fully utilized for this purpose. Here, we review the existing knowledge on the eco-epidemiology of VBR in Taiwan and recommend future courses of action.