MyMedR

Isolation of rickettsiae from patients' blood samples and organ samples of wild rodents from areas with high seroprevalence of rickettsial infections was attempted using cell culture assay and animal passages. L929 mouse fibroblast cells grown in 24 well tissue culture plate were inoculated with buffy coat of febrile patients and examined for the growth of rickettsiae by Giemsa, Gimenez staining and direct immunofluorescence assay. No rickettsiae were isolated from 48 patients' blood samples. No symptomatic infections were noted in mice or guinea pigs infected with 50 organ samples of wild rodents. There was no rickettsial DNA amplified from these samples using various PCR detection systems for Orientia tsutsugamushi, typhus and spotted fever group rickettsiae.

Matched MeSH terms: Rodent Diseases/blood; Rodent Diseases/immunology; Rodent Diseases/microbiology*; Rodent Diseases/epidemiology

Fulltext Isolation and molecular identification of Bartonellae from wild rats (Rattus species) in Malaysia

Tay ST, Mokhtar AS, Zain SN, Low KC

Am J Trop Med Hyg, 2014 Jun;90(6):1039-42.

PMID: 24732465 DOI: 10.4269/ajtmh.13-0273

This study describes our investigation on the prevalence and molecular identification of bartonellae from Rattus diardii and R. norvegicus in the urban areas of Malaysia. Of 95 rats investigated, Bartonella tribocorum, B. rattimassiliensis, B. coopersplainsensis, B. elizabethae, and B. queenslandensis were isolated from kidney and spleen homogenates of four rats. Bartonellae DNA was amplified from the rat organ tissues by using primers specific for the bartonellae RNA polymerase beta subunit (rpoB) gene in nine other rats. Sequence analysis of the rpoB gene fragments shows the identification of B. queenslandensis in five rats, B. elizabethae in three rats, and B. tribocorum in one rat. Combining the results of isolation and molecular detection of bartonellae, we found that the prevalence of Bartonella infection in the Rattus spp. investigated in this study was 13.7%. Implementation of effective rat control program in the urban areas is necessary to prevent the spillover of bartonellosis from rats to humans.

Matched MeSH terms: Rodent Diseases/microbiology; Rodent Diseases/epidemiology*

A new rhabditoid nematode species in Asian sciurids, distinct from Strongyloides robustus in North American sciurids

Sato H, Torii H, Une Y, Ooi HK

J Parasitol, 2007 Dec;93(6):1476-86.

PMID: 18314696 DOI: 10.1645/GE-1106.1

Strongyloides callosciureus n. sp. (Nematoda: Rhabditoidea), from Asian sciurids, is described based on morphology, morphometry, and the small and large subunit (SSU/LSU) ribosomal RNA gene (rDNA) sequences. This new species was collected from Pallas's squirrels (Callosciurus erythraeus) in the central part of mainland Japan (Honshu), which were originally introduced from Taiwan some decades ago, and plantain squirrels (Callosciurus notatus) imported from Malaysia as personal pets. For comparison, Strongyloides robustus Chandler, 1942 was collected from American red squirrels (Tamiasciurus hudsonicus) and southern flying squirrels (Glaucomys volans) imported from the United States as personal pets. The parasitic females found in North American and Asian sciurids shared some key morphological features such as the ovary running spirally around the gut, and the shapes of the stoma in the apical view and the tail. However, morphometric features of parasitic females in North American and Asian sciurids differed significantly from each other; the former was larger than the latter, and the relative position of the vulva to the whole body length from the mouth was different. The SSU/LSU rDNA sequences supported the division of sciurid Strongyloides isolates by geographical distribution of the host and morphological features, leading us to propose the erection of new species.

Matched MeSH terms: Rodent Diseases/epidemiology; Rodent Diseases/parasitology*

Fulltext Comparison between Quantitative Buffy Coat (QBC) and Giemsa-stained Thin Film (GTF) technique for blood protozoan infections in wild rats

Sahimin N, Alias SN, Woh PY, Edah MA, Mohd Zain SN

Trop Biomed, 2014 Sep;31(3):422-31.

PMID: 25382468 MyJurnal

The quantitative buffy coat (QBC) technique and conventional Giemsa thin blood smear was compared to determine the sensitivity and specificity of the technique in detecting blood parasitic infection of the rodent populations from four urban cities in Peninsular Malaysia. A total of 432 blood samples from four rat species (Rattus norvegicus, Rattus rattus diardii, Rattus exulans and Rattus argentiventer) were screened using both techniques and successfully detected two blood protozoan species (Trypanosoma lewisi and Plasmodium sp.) with Trypanosoma lewisi predominantly infecting the population. Results showed that Giemsa-stained thin film (GTF) was the better detection method on blood parasitemia (46.7%) compared to Quantitative Buffy Coat method (38.9%) with overall detection technique sensitivity and specificity at 83.2% and 74.8% respectively. The sensitivity in detection of Trypanosoma lewisi was 84.4% with value slightly lower for Plasmodium sp. infections at 76.6%. Statistical analysis proved that GTF technique was significantly more sensitive in the detection of blood protozoan infections in the rodent population compared to QBC (p<0.05).

Matched MeSH terms: Rodent Diseases/diagnosis*; Rodent Diseases/parasitology

Identification of rickettsiae from wild rats and cat fleas in Malaysia

Tay ST, Mokhtar AS, Low KC, Mohd Zain SN, Jeffery J, Abdul Aziz N, et al.

Med Vet Entomol, 2014 Aug;28 Suppl 1:104-8.

PMID: 25171613 DOI: 10.1111/mve.12075

Rickettsioses are emerging zoonotic diseases reported worldwide. In spite of the serological evidence of spotted fever group rickettsioses in febrile patients in Malaysia, limited studies have been conducted to identify the animal reservoirs and vectors of rickettsioses. This study investigated the presence of rickettsiae in the tissue homogenates of 95 wild rats and 589 animal ectoparasites. Using PCR assays targeting the citrate synthase gene (gltA), rickettsial DNA was detected in the tissue homogenates of 13 (13.7%) wild rats. Sequence analysis of the gltA amplicons showed 98.6-100% similarity with those of Rickettsia honei/R. conorii/R. raoultii (Rickettsiales: Rickettsiaceae). Sequence analysis of outer membrane protein A gene (ompA) identified Rickettsia sp. TCM1 strain from two rats. No rickettsia was detected from Laelaps mites, Rhipicephalus sanguineus and Haemaphysalis bispinosa ticks, and Felicola subrostratus lice in this study. R. felis was identified from 32.2% of 177 Ctenocephalides felis fleas. Sequence analysis of the gltA amplicons revealed two genotypes of R. felis (Rf31 and RF2125) in the fleas. As wild rats and cat fleas play an important role in the enzoonotic maintenance of rickettsiae, control of rodent and flea populations may be able to reduce transmission of rickettsioses in the local setting.

Matched MeSH terms: Rodent Diseases/microbiology; Rodent Diseases/epidemiology*

Observations on the development of a new filaria (Breinlia booliati, Singh and Ho, 1973) of a rat Rattus sabanus in the mosquito Aedes togoi

Ho BC, Singh M, Lim BL

J Helminthol, 1973;47(2):135-40.

PMID: 4724313

Matched MeSH terms: Rodent Diseases

Involvement of small mammals in the transmission of scrub typhus in Malaysia: isolation and serological evidence

Walker JS, Gan E, Chan Teik Chye, Muul I

Trans R Soc Trop Med Hyg, 1973;67(6):838-45.

PMID: 4207572

Matched MeSH terms: Rodent Diseases/microbiology

Fulltext Leptospira interrogans and Leptospira kirschneri are the dominant Leptospira species causing human leptospirosis in Central Malaysia

Philip N, Bahtiar Affendy N, Ramli SNA, Arif M, Raja P, Nagandran E, et al.

PLoS Negl Trop Dis, 2020 Mar;14(3):e0008197.

PMID: 32203511 DOI: 10.1371/journal.pntd.0008197

BACKGROUND: Leptospirosis, commonly known as rat-urine disease, is a global but endemic zoonotic disease in the tropics. Despite the historical report of leptospirosis in Malaysia, the information on human-infecting species is limited. Determining the circulating species is important to understand its epidemiology, thereby to strategize appropriate control measures through public health interventions, diagnostics, therapeutics and vaccine development.

METHODOLOGY/PRINCIPLE FINDINGS: We investigated the human-infecting Leptospira species in blood and serum samples collected from clinically suspected leptospirosis patients admitted to three tertiary care hospitals in Malaysia. From a total of 165 patients, 92 (56%) were confirmed cases of leptospirosis through Microscopic Agglutination Test (MAT) (n = 43; 47%), Polymerase Chain Reaction (PCR) (n = 63; 68%) or both MAT and PCR (n = 14; 15%). The infecting Leptospira spp., determined by partial 16S rDNA (rrs) gene sequencing revealed two pathogenic species namely Leptospira interrogans (n = 44, 70%) and Leptospira kirschneri (n = 17, 27%) and one intermediate species Leptospira wolffii (n = 2, 3%). Multilocus sequence typing (MLST) identified an isolate of L. interrogans as a novel sequence type (ST 265), suggesting that this human-infecting strain has a unique genetic profile different from similar species isolated from rodents so far.

CONCLUSIONS/SIGNIFICANCE: Leptospira interrogans and Leptospira kirschneri were identified as the dominant Leptospira species causing human leptospirosis in Central Malaysia. The existence of novel clinically important ST 265 (infecting human), that is different from rodent L. interrogans strains cautions reservoir(s) of these Leptospira lineages are yet to be identified.

Matched MeSH terms: Rodent Diseases

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