Ectoparasites of murids in peninsular Malaysia and their associated diseases

Great genetic diversity of vector-borne bacteria and protozoan in wild rodents from Guangxi, China

BACKGROUND

Rodents are recognized as the hosts of many vector-borne bacteria and protozoan parasites and play an important role in their transmission and maintenance. Intensive studies have focused on their infections in vectors, especially in ticks, however, vector-borne bacterial and protozoan infections in rodents are poorly understood although human cases presenting with fever may due to their infection have been found.

METHODS

From May to October 2019, 192 wild rodents were trapped in wild environment of Guangxi Province, and the spleen samples were collected to reveal the presence of vector-borne bacterial and protozoan infections in them. The microorganisms in rodents were identified by detecting their DNA using (semi-)nested PCR. All the PCR products of the expected size were subjected to sequencing, and then analyzed by BLASTn. Furthermore, all the recovered sequences were subjected to nucleotide identity and phylogenetic analyses.

RESULTS

As a result, 192 rodents representing seven species were captured, and Bandicota indica were the dominant species, followed by Rattus andamanensis. Based on the (semi-)nested PCR, our results suggested that Anaplasma bovis, Anaplasma capra, Anaplasma ovis, Anaplasma phagocytophilum, "Candidatus Neoehrlichia mikurensis", "Candidatus E. hainanensis", "Candidatus E. zunyiensis", three uncultured Ehrlichia spp., Bartonella coopersplainsensis, Bartonella tribocorum, Bartonella rattimassiliensis, Bartonella silvatica, two uncultured Bartonella spp., Babesia microti and diverse Hepatozoon were identified in six rodent species. More importantly, six species (including two Anaplasma, two Bartonella, "Ca. N. mikurensis" and Bab. microti) are zoonotic pathogens except Anaplasma bovis and Anaplasma ovis with zoonotic potential. Furthermore, dual infection was observed between different microorganisms, and the most common type of co-infection is between "Ca. N. mikurensis" and other microorganisms. Additionally, potential novel Bartonella species and Hepatozoon species demonstrated the presence of more diverse rodent-associated Bartonella and Hepatozoon.

CONCLUSIONS

The results in this work indicated great genetic diversity of vector-borne infections in wild rodents, and highlighted the potential risk of human pathogens transmitted from rodents to humans through vectors.

Cross-sectional seasonal prevalence and relative risk of ectoparasitic infestations of rodents in North Sinai, Egypt

Background and Aim:

Rodents are ubiquitous animals that host ectoparasites and transmit zoonotic diseases. We conducted a cross-sectional study on the seasonal variation, period prevalence (Pp), and relative risk of ectoparasitic infestations in rodents collected in North Sinai, Egypt, from September 2019 to August 2020.

Materials and Methods:

We captured 380 rodents during the study period. Rodents were euthanized to perform species identification, and 2930 external parasites were collected and identified using light microscopic examination with systemic keys depending on morphological characters.

Results:

Rattus norvegicus (brown rat), Rattus rattus frugivorus (white-bellied rat), Rattus rattus alexandrines (gray-bellied rat), and Mus musculusdomesticus (house mouse) were captured at the highest frequencies during summer (n=186), followed by spring (n=84), fall (n=71), and winter (n=39), with a higher proportion of males captured in all seasons. Analysis of the infestation Pp revealed highly significant increases (p<0.01) in ectoparasites during the winter. Temperature, humidity, and dew point were significantly (p<0.01) correlated with the numbers of captured and infested rodents. Parasitological examinations showed the higher risks of flea (Echidnophaga gallinacea, Xenopsylla cheopis, and Leptopsylla segnis) and lice (Hoplopleura hirsuta, Hoplopleura ocanthopus, Hoplopleura oenomydis, and Polyplax spinulosa) infestations during winter and mite (Laelaps nuttalli, Dermanyssus gallinae, Ornithonyssus bacoti, and Myobia musculi) infestations during summer.

Conclusion:

We conclude that ectoparasitic infestation prevalence and risk varies with predominating macroclimatic conditions. Strict preventive and biosecurity measures should be applied to combat rodent-related problems.

Human Ectoparasites Are Highly Prevalent in the Rural Communities of Northwest Ethiopia: A Community-Based Cross-Sectional Study

BACKGROUND

Ectoparasites are organisms which inhabit the skin or outgrowths of the skin of another organism (the host). Many ectoparasites are known to be vectors of pathogens, which the parasites typically transmit to hosts. Though, ectoparasites are common in the vulnerable groups and economically disadvantaged communities, there is limited evidence on its magnitude in Ethiopia. This community-based cross-sectional study was, therefore, conducted to assess the prevalence and associated factors of ectoparasites in the rural communities of northwest Ethiopia.

METHODS

A community-based cross-sectional study design with structured observation was conducted among 1191 randomly selected rural households in northwest Ethiopia in May 2016. Data were collected using structured interviewer administered interview questionnaire and structured observation checklist. Prevalence of human ectoparasites in the rural communities was defined as the presence of one or more lice, fleas, bed bugs, mites, and ticks and the presence of these ectoparasites were observed by trained environmental health experts. Multivariable binary logistic regression analysis was used to identify variables associated with prevalence of ectoparasites on the basis of adjusted odds ratio (AOR) with 95% confidence interval (CI) and P values <.05.

RESULTS

Of a total of 1191 rural households, human or hair lice were observed in one or more of the family members in 186 (15.6%) rural households. Similarly, fleas were observed in more than half, 609 (51.1%) of rural households and bed bugs were observed in 441 (37%) rural households. Furthermore, mites and ticks were reported in 113 (9.5%) and 130 (10.9%) of the households respectively. Accordingly, one or more ectoparasites were observed in 865 of 1191 rural households. The presence of one or more ectoparasites was, therefore, found to be 72.6% (95% CI = 70%-75.1%). The prevalence of ectoparasites was statistically associated with educational status of the female head being not educated (AOR = 1.476, 95% CI = 1.001, 2.177) and absence close supervision by health extension workers (AOR = 2.151, 95% CI = 1.205, 3.843).

CONCLUSION

The prevalence of one or more ectoparasites was high in the rural communities of northwest Ethiopia. The high prevalence was associated with education status of the female head and close supervision of households by health extension workers. Disseminating health information about intervention strategies of ectoparasites and closely supervising the rural households need to be considered.

Molecular genotypes analysis of Cryptosporidium and Hymenolepis in rats on Lombok Island, Indonesia

Background and Aim: Cryptosporidium parvum and Hymenolepis nana are intestinal parasites that are commonly found in the unclean environment. Their presence in rats promotes the transmission of the cryptosporidiosis and hymenolepiasis to humans or animals nearby. This study aimed to determine the molecular characteristics of C. parvum and H. nana and their distribution in rats on Lombok Island. Materials and Methods: C. parvum and H. nana were investigated in 50 rats from Lombok Island. The molecular-parasitological technique used was polymerase chain reaction and sequencing method. Results: From 50 samples of rats' stool from 10 locations on Lombok Island, 8% (4/50) of C. parvum was detected molecularly with an 18S rRNA gene and 2% (1/50) of H. nana with COX 1 gene. Phylogenetic analysis indicated that C. parvum carrying rats on Lombok Island have a genetic relationship with C. parvum with Obi7 isolates, Japan and H. nana has a genetic relationship with Rodentolepis nana identified with Hn-VT isolates, India. Conclusion: The highest incidence of parasites was found in rats that were caught in the urban areas of Lombok Island, West Nusa Tenggara, Indonesia. Immediately, public health programs in these types of contaminated areas should receive priority attention to prevent further transmission of the parasites from animals to human beings.

Review of Mites Found on Various Animal Hosts and at Different Localities in Malaysia

Mite biodiversity and distribution in Malaysia is currently understudied. Most previous works on Malaysian Acari have focused on pest organisms of medical, veterinary, and agricultural concern, with a few recent studies centered on mites in forensic contexts. Previous literatures have targeted collection sites in forest reserves and/or mountains in either Peninsular or Malaysian Borneo, though the state of Sarawak had the least publications related to mite species descriptions despite having the highest number of nature parks of any state in the country. Most publications focused on the three states Selangor, Pahang and Sabah. Most of the mite species reported were from mammals (66.3%), with fewer species from birds (21.7%), arthropods (11.2%), and reptiles (0.8%). We believe that further work on the systematic documentation of mite species throughout Malaysia is necessary as it could generate useful tools, such as the use of mites as biogeographical markers or as forensic indicators. Therefore, this review catalogs mite species that have been documented in or on animal hosts in Malaysia and serves as a foundation for future work.

Ticks and tick-borne pathogens in animals and humans in the island nations of Southeast Asia: A review

Ticks are blood-feeding ectoparasites and major vectors of pathogens that cause infectious diseases in humans and animals worldwide including mammals, birds and reptiles. Despite the growing scientific effort in the 20th century, there is still limited information on ticks and tick-borne pathogens in Southeast Asia, especially concerning medical, veterinary, socioeconomic and agricultural aspects in the island nations. This review provides an overview of the current state of knowledge of ticks and their pathogens in the island nations of Southeast Asia and peninsular Malaysia. We aim to stimulate further research studies on ticks and tick-borne pathogens of human and veterinary importance in this geographical region.

Rickettsiae exposure related to habitats of the oriental house rat (Rattus tanezumi, Temminck, 1844) in Salaya suburb, Thailand

Rickettsial zoonotic diseases, in particular scrub typhus, murine typhus, and tick typhus, are caused by Orientia tsutsugamushi, Rickettsia typhi, and Rickettsia honei infections. Rickettsiae exposure is typically related to a rodent host in various habitats of marginal regions, including between rural areas and communities such as the Salaya suburb. This allows the oriental house rat (OHR), a highly adaptive species, to live in close proximity to the community and possibly introduce rickettsial diseases. To understand rickettsial exposure in the OHR from different habitats, knowledge of disease exposure can serve as baseline information for disease management and prevention. A total of 185 OHRs from three unrelated habitats were assessed using a standard indirect immunofluorescence assay (IFA) for specific antibody reaction to O. tsutsugamushi, R. typhi, and R. honei. The presence of antibody in the OHR to rickettsiae, either scrub or murine typhus, was associated with the habitat, whereas tick typhus had general exposure. This finding shows the OHR to be a potential reservoir host for rickettsial diseases along the borders of geographic regions in the suburban environment.

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Oriental house rat, a highly adaptive species to various habitat was harbored the several infectious organisms.

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Serological survey; scrub, murine and tick typhus were similarly found in oriental house rat.

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Scrub and murine typhus were consistent with individual habitat but tick typhus.

Detection of rodent-borne parasitic pathogens of wild rats in Serdang, Selangor, Malaysia: A potential threat to human health

Rodent species, such as Rattus rattus diardii and Rattus norvegicus are invasive species of wild rats that serve as potential reservoirs of important human's pathogens. Parasitic zoonosis accounts for over 60% of all human infectious diseases worldwide. This situation arises from the recent changes in the global climate and ecosystem composition, which led to the spread of rodents and rodent-borne pathogens globally. The aim of this study was to determine the occurrence of rodent's parasites and their zoonotic potentials in some selected areas in UPM. Rodents were captured using live-traps and euthanised for helminths and protozoan recovery. Intestinal parasites were detected and identified from stool samples using formalin ethyl-acetate concentration technique (FECT), while tissue parasites were identified by histopathological examination of selected tissue sections of the liver, brain, lungs, and muscle. In this study, a total of 89 wild rats were captured. Twelve species of intestinal and tissue parasites were recorded, of which, Taenia taeniaeformis accounts for the highest infection recorded (28%) followed by Hymenolepis nana (19.5%) and Capillaria hepatica (19.1%), while Toxoplasma gondii was the least parasite (6.7%) identified. Furthermore, other parasites species observed include, Cryptosporidium spp. (21.3%), Entamoeba histolytica/Entamoeba dispar and Moniliformis moniliformis (17.9%), Angiostrongylus cantonensis (16.8%), Hymenolepis diminuta (16.1%), Giardia spp. (14.6%), Trichuris spp. (12.3%), and Sarcocystis spp. (6.74). Based on the results obtained in the present study, 17.1% and 15.4% of the rodents captured were confirmed positive for at least one species of intestinal or tissue parasites, respectively. The presence of these zoonotic parasites in the wild rats suggests the potential risk of rodent-borne zoonotic disease transmission to humans. Hence, the need to improved rats control intervention and public health awareness among the populace.