High Seroprevalence of Antibodies against Spotted Fever and Scrub Typhus Bacteria in Patients with Febrile Illness, Kenya - Volume 21, Number 4—April 2015 - Emerging Infectious Disease journal - CDC

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High Seroprevalence of Antibodies against Spotted Fever and Scrub Typhus Bacteria in Patients with Febrile Illness, Kenya - Volume 21, Number 4—April 2015 - Emerging Infectious Disease journal - CDC

Volume 21, Number 4—April 2015

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High Seroprevalence of Antibodies against Spotted Fever and Scrub Typhus Bacteria in Patients with Febrile Illness, Kenya

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• The Study
• Conclusions
• Suggested Citation

Figures

• Figure 1
• Figure 2

Tables

• Table

Technical Appendicies

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Jacqueline W. Thiga, Beth K. Mutai, Wurapa K. Eyako, Zipporah Ng’ang’a, Ju Jiang, Allen L. Richards, and John N. Waitumbi 

Author affiliations: Walter Reed Project/Kenya Medical Research Institute, Kisumu, Kenya (J.W. Thiga, B.K. Mutai, W.K. Eyako, J.N. Waitumbi); Jomo Kenyatta University of Agriculture and Technology, Itromid, Nairobi, Kenya (J.W. Thiga, Z. Ng’ang’a); Naval Medical Research Center, Silver Spring, Maryland, USA (J. Jiang, A.L. Richards)

Suggested citation for this article

Abstract

Serum samples from patients in Kenya with febrile illnesses were screened for antibodies against bacteria that cause spotted fever, typhus, and scrub typhus. Seroprevalence was 10% for spotted fever group, <1% for typhus group, and 5% for scrub typhus group. Results should help clinicians expand their list of differential diagnoses for undifferentiated fevers.

Rickettsioses are zoonoses that are increasingly being recognized as noteworthy infectious diseases (1). They are caused by bacteria of the genera Rickettsia and Orientia, which are small, gram-negative, obligate intracellular bacteria that are transmitted to humans through bites of infected arthropod vectors, such as fleas, mites, ticks, and lice. These bacteria are able to invade various host cells, including vascular endothelium, causing characteristic symptoms such as rash and petecchial hemorrhages. The genus Rickettsia is divided into 2 main biogroups: spotted fever group (SFG) and typhus group (TG). The scrub typhus group (STG) previously belonged to the genus Rickettsia but now belongs to the genus Orientia (2), which consists of 2 species: O. tsutsugamushiand O. chuto (3).

The past 5 years have seen concerted efforts to understand the etiology of undifferentiated febrile illnesses, a group of diseases that includes rickettsioses. These efforts have confirmed the occurrence of infections with R. felis, transmitted mainly by the cat flea (Ctenocephalides felis felis), as a common cause of fever in rural areas (4–6). Studies have also shown the preponderance of R. africae, the causative agent of African tick-bite fever, as well as R. conorii and R. aeschlimannii, in different ecoregions of Kenya (7). The study reported here is part of a broader study aimed at identifying pathogens or their surrogates, such as immunoglobulins, in patients with febrile illnesses. It is hoped that these types of reports will help local clinicians expand their list of differential diagnoses for undifferentiated fevers.

At the time of this study, Ms. Thiga was a master of science student at the Jomo Kenyatta University of Agriculture and Technology. Her research interests include rickettsial diagnosis and epidemiology.

Acknowledgments

We are grateful to the patients for taking part in this study. We thank project staff, including medical officers, nurses, and laboratory technicians. This work is published with the permission of the director, Kenya Medical Research Institute.

Financial support for this study was from a grant from the Global Emerging Infection System and Division of the Armed Forces Health Surveillance Center.

References

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Figures

• Figure 1. Distribution of titers to spotted fever (SFG) and scrub typhus (STG) groups in patients recruited in various surveillance hospitals. A) For SFG, Garissa District Hospital (GSA), in semiarid northeastern...
• Figure 2. Western blot analysis using the Orientia spp.–specific antigen (Otr47b). Twenty scrub typhus reactive serum samples at a titer ≥1:6,000 were used. Negative controls were serum samples that were reactive...

Table

• Table. Demographic characteristics of febrile patients tested for seropositivity for SFG and STG rickettsioses, Kenya

Technical Appendix

• . Additional information regarding seroprevalence of IgG against spotted fever group rickettsiae and scrub typhus in patients recruited from different surveillance hospitals in Kenya  64 KB

Suggested citation for this article: Thiga JW, Mutai BK, Eyako WK, Ng’ang’a Z, Jiang J, Richards AL, et al. High seroprevalence of antibodies against spotted fever and scrub typhus bacteria in patients with febrile illness, Kenya. Emerg Infect Dis [Internet]. 2015 Apr [date cited].http://dx.doi.org/10.3201/eid2104.141387

DOI: 10.3201/eid2104.141387