Abstract:Little is known of the endemicity of flea-borne rickettsiae in Kazakhstan. Thus, a survey for rickettsiae within great gerbil fleas was conducted in Almaty oblast. High prevalence of Rickettsia asembonensis was detected among Xenopsylla gerbilli, demonstrating that flea-borne rickettsiae are endemic to southeastern Kazakhstan. Interestingly, no Rickettsia typhi were detected in these same fleas.
“…High prevalence rates of R. asembonensis have been reported in C. felis and C. canis (sympatric species), S. pallidus, X. ramesis , and X. gerbilli with up to 95, 95, 91.4, 100, and 33.3% of the fleas positive for R. asembonensis , respectively (13, 14, 18, 40, 46). Similar results in Costa Rica and Brazil confirm the high prevalence of R. asembonensis in C. felis (23, 28).…”
Section: Arthropods Associated With Rickettsia Asembonensismentioning
confidence: 99%
“…These include E. gallinacea, P. irritans, C. lamellifer, X. hirtipes , and N. laeviceps . Often these fleas are positive for R. asembonensis in the same areas as fleas highly infected with R. asembonensis (14, 46). The presence of the R. asembonensis in minimally infected flea species may be due to co-feeding and not that these fleas are reservoir hosts for R. asembonensis .…”
Section: Arthropods Associated With Rickettsia Asembonensismentioning
Rickettsia asembonensis, the most well-characterized rickettsia of the Rickettsia felis-like organisms (RFLO), is relatively unknown within the vector-borne diseases research community. The agent was initially identified in peri-domestic fleas from Asembo, Kenya in an area in which R. felis was associated with fever patients. Local fleas collected from domestic animals and within homes were predominately infected with R. asembonensis with < 10% infected with R. felis. Since the identification of R. asembonensis in Kenya, it has been reported in other locations within Africa, Asia, the Middle East, Europe, North America, and South America. With the description of R. asembonensis-like genotypes across the globe, a need exists to isolate these R. asembonensis genotypes in cell culture, conduct microscopic, and biological analysis, as well as whole genome sequencing to ascertain whether they are the same species. Additionally, interest has been building on the potential of R. asembonensis in infecting vertebrate hosts including humans, non-human primates, dogs, and other animals. The current knowledge of the presence, prevalence, and distribution of R. asembonensis worldwide, as well as its arthropod hosts and potential as a pathogen are discussed in this manuscript.
“…High prevalence rates of R. asembonensis have been reported in C. felis and C. canis (sympatric species), S. pallidus, X. ramesis , and X. gerbilli with up to 95, 95, 91.4, 100, and 33.3% of the fleas positive for R. asembonensis , respectively (13, 14, 18, 40, 46). Similar results in Costa Rica and Brazil confirm the high prevalence of R. asembonensis in C. felis (23, 28).…”
Section: Arthropods Associated With Rickettsia Asembonensismentioning
confidence: 99%
“…These include E. gallinacea, P. irritans, C. lamellifer, X. hirtipes , and N. laeviceps . Often these fleas are positive for R. asembonensis in the same areas as fleas highly infected with R. asembonensis (14, 46). The presence of the R. asembonensis in minimally infected flea species may be due to co-feeding and not that these fleas are reservoir hosts for R. asembonensis .…”
Section: Arthropods Associated With Rickettsia Asembonensismentioning
Rickettsia asembonensis, the most well-characterized rickettsia of the Rickettsia felis-like organisms (RFLO), is relatively unknown within the vector-borne diseases research community. The agent was initially identified in peri-domestic fleas from Asembo, Kenya in an area in which R. felis was associated with fever patients. Local fleas collected from domestic animals and within homes were predominately infected with R. asembonensis with < 10% infected with R. felis. Since the identification of R. asembonensis in Kenya, it has been reported in other locations within Africa, Asia, the Middle East, Europe, North America, and South America. With the description of R. asembonensis-like genotypes across the globe, a need exists to isolate these R. asembonensis genotypes in cell culture, conduct microscopic, and biological analysis, as well as whole genome sequencing to ascertain whether they are the same species. Additionally, interest has been building on the potential of R. asembonensis in infecting vertebrate hosts including humans, non-human primates, dogs, and other animals. The current knowledge of the presence, prevalence, and distribution of R. asembonensis worldwide, as well as its arthropod hosts and potential as a pathogen are discussed in this manuscript.
“…The commonly used method of preparing arthropod vectors is to employ pooling, which groups the same arthropod species from one location, the same host, or drag/flag sheet into one pool sample (94). The pool samples can be restricted to individuals of the same arthropod species and life stage.…”
Cooperative research that addresses infectious disease surveillance and outbreak investigations relies heavily on availability and effective use of appropriate diagnostic tools, including serological and molecular assays, as exemplified by the current COVID-19 pandemic. In this paper, we stress the importance of using these assays to support collaborative epidemiological studies to assess risk of rickettsial disease outbreaks among international partner countries. Workforce development, mentorship, and training are important components in building laboratory capability and capacity to assess risk of and mitigate emerging disease outbreaks. International partnerships that fund cooperative research through mentoring and on-the-job training are successful examples for enhancing infectious disease surveillance. Cooperative research studies between the Naval Medical Research Center's Rickettsial Diseases Research Program (RDRP) and 17 institutes from nine countries among five continents were conducted to address the presence of and the risk for endemic rickettsial diseases. To establish serological and molecular assays in the collaborative institutes, initial training and continued material, and technical support were provided by RDRP. The laboratory methods used in the research studies to detect and identify the rickettsial infections included (1) group-specific IgM and IgG serological assays and (2) molecular assays. Twenty-six cooperative research projects performed between 2008 and 2020 enhanced the capability and capacity of 17 research institutes to estimate risk of rickettsial diseases. These international collaborative studies have led to the recognition and/or confirmation of rickettsial diseases within each of the partner countries. In addition, with the identification of specific pathogen and non-pathogen Rickettsia species, a more accurate risk assessment could be made in surveillance studies using environmental samples. The discoveries from these projects reinforced international cooperation benefiting not only the partner countries but also the scientific community at large through presentations (n = 40) at international scientific meetings and peer-reviewed publications (n = 18). The cooperative research studies conducted in multiple international institutes led to the incorporation of new SOPs and trainings for laboratory procedures; biosafety, biosurety, and biosecurity methods; performance of rickettsia-specific assays; and the identification of known and unknown rickettsial agents through the introduction of new serologic and molecular assays that complemented traditional microbiology methods.
“…Although murine typhus is considered to be a mild disease, delayed antibiotic therapy is a major factor of poor prognosis in patients [17] . Considering that fleaborne rickettsiae are endemic to Kazakhstan and the fact that fevers of unknown origin are often registered in southern Kazakhstan, the purpose of this study was to evaluate the prevalence of IgG antibodies to R. typhi in a population of southern Kazakhstan [18] .…”
Background.Rickettsia typhi belongs to the typhus group of rickettsiae and causes endemic typhus. Cases of endemic typhus and seropositivity to R. typhi have been reported in the neighbouring China and Russia. However, little is known of the endemic typhus in Kazakhstan. The purpose of this study was to evaluate the prevalence of IgG antibodies to R. typhi in the population of southern region of Kazakhstan. Methods. A total of 253 individuals (142 women, 111 men) aged from 1 to 71 years were recruited into the study. Detection of serum IgG antibodies against R. typhi was performed by enzyme-linked immunosorbent assay (ELISA). Results. The overall R. typhi seropositivity has reached 34.4%. The highest seroprevalence of 91.8% was recorded in the Turkestan Region. The lowest seropositivity of 6.1% was detected in the village Lepsinsk, Almaty Region. The seroprevalence did not differ significantly between genders. Seropositivity in adult individuals was not significantly associated with age, but positive results were not detected in the age group of children under 14 years. Conclusion. The obtained results confirm active circulation of R. typhi in the Turkestan and Almaty Regions of Kazakhstan. The data indicate an urgent need for further studies aimed to evaluate the clinical impact caused by R. typhi in the southern region of Kazakhstan.
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