The Borrelia genus consists of spirochete bacteria known to cause Lyme disease (LD) and relapsing fever in humans. Borrelia pathogens are commonly transmitted via arthropod vectors such as ticks, mites, or lice. Here, we report the molecular screening of LD group Borrelia sp. from ticks (Acari: Ixodidae) collected from rodents trapped in recreational forests and a semiurban residential area in the Selangor state in Malaysia. Of 156 adult ticks surveyed, 72 ticks were determined as positive for Borrelia sp. by polymerase chain reaction (PCR). All Borrelia PCR-positive ticks belonged to the Ixodes granulatus Supino species. Borrelia sp. was not detected in other tick species examined, including Dermacentor sp. and Amblyomma sp. ticks. Thirteen Borrelia PCR-positive tick samples were selected for further sequence analyses. Phylogenetic analyses of partial flaB gene sequences revealed that the Borrelia sp. were closely related to the LD group borreliae, Borrelia yangtzensis; a novel Borrelia genospecies reported in East Asian countries including Japan, Taiwan, and China. To our knowledge, this is the first report of Borrelia sp. related to Borrelia yangtzensis detected in Malaysia and Southeast Asia. The zoonotic potential of the Borrelia sp. reported here merits further investigation, as it may explain the previously reported serological evidence for borrelial infections in Malaysia.
Leptospira interrogans serovar Bataviae was recently identified as one of the persistent Leptospira serovars in Malaysia. Here, we report the draft genome sequence of the L. interrogans serovar Bataviae strain LepIMR 22 isolated from kidney of a rodent in Johor, Malaysia.
A total of 204 rodents comprising 14 host species from four different habitats were examined. Nine rodent species were trapped from the forest and another five species were trapped from the coastal, rice field and urban habitats. Rattus rattus diardii (67%) was the predominant rodent species examined. Fifty six (47.3%) rodents and shrews were found to be infested with at least one of the 20 species of ectoparasite recovered. Mites belonging to the family Trombiculidae were the predominant ectoparasite species recovered. Ticks belonging to the family Ixodidae were recovered mainly from the forest dwelling rodents. Polyplax spinulosa and Hoplopleura pacifica were the common lice species found infesting the urban rodents. Xenopsylla cheopis was the only flea species recovered. The following ecto-parasites have been incriminated as important vectors or as mechanical carriers for the transmission of zoonotic diseases: Ixodes granulatus, Dermacentor sp. Haemaphysalis sp., Amblyomma sp. Ascoschoengastia indica, Leptotrombidium deliense, Ornithonyssus bacoti, Laelaps nuttalli, H. pacifica, P. spinulosa and Xenopsylla cheopis. Urban and forest rodents were significantly higher in ecto-parasitic infestation, compared to rats from the other two habitats. However, there was no significant statistical association between male and female rodents infested with ectoparasites.
Field surveys of ectoparasites on rodents and scandents were conducted in four localities of wildlife reserves in Peninsular Malaysia from October 2008 to November 2009. A total of 16 animals comprising 5 species of hosts were caught and examined for ectoparasites. The hosts examined were Maxomys rajah, Maxomys whiteheadi, Leopoldamys sabanus, Lariscus insignis and Tupaia glis. Of these hosts, 9 genera, consisting of 14 species of ectoparasites were extracted. Three species of ticks (Ixodidae), 7 species of mesostigmatid mites (Laelaptidae), 3 species of chiggers (Trombiculidae) and 1 species of listrophorid mites (Listrophoriidae) were identified. The infestation rate of ectoparasites observed ranged from 12.5% to 62.5%. Among the ectoparasites found, Ixodes granulatus and Leptotrombidium deliense are of known medical importance.
Diabetes mellitus remains an incurable disorder in spite of intense research. As result of limitations and unmet goals associated with the use of anti-diabetic drugs, an increased number of diabetic populations globally now resort to complementary and alternative medicine (CAM) such as herbs and other natural products. There has been a renewed interest in the use of honey in the treatment of diabetes mellitus, partly due to an increase in the availability of evidence-based data demonstrating its benefits in diabetic rodents and patients. This commentary aims to underscore some of the research implications, issues and questions raised from these studies which show the beneficial effects of honey in the treatment of diabetes mellitus. Some of the issues highlighted in this article include: considering honey is sweet and rich in sugars, how could it be beneficial in the management of diabetes mellitus? Are the observed effects of honey or combined with anti-diabetic drugs exclusive to certain honey such as tualang honey? Could these beneficial effects be reproduced with other honey samples? Anti-diabetic drugs in combination with honey improve glycemic control, enhance antioxidant defenses and reduce oxidative damage. These effects are believed to be mediated partly via antioxidant mechanism of honey. This raises another question. Could similar data be obtained if anti-diabetic drugs are co-administered with other potent antioxidants such as vitamin C or E? As the evidence has revealed, the prospect of managing diabetes mellitus with honey or antioxidants (such as vitamin C or E) as an adjunct to conventional diabetes therapy is vast. However, more well-designed, rigorously conducted randomized controlled studies are necessary to further validate these findings.
Hantavirus is a serious disease caused by rodents which can lead to mortality. Many efforts have been carried out by researchers to develop and analyze mathematical models of Hantavirus infection. In this paper, the Peixoto and Abramson (2006) biodiversity model is modified to include the effect of predators and study the prediction of the modified model. When rodent and predator populations are in competition, the predator populations have the effect of reducing the prevalence of infection. Predators may be used for control and reduces the number of competing species to stabilize the populations at a persistent equilibrium.
In this paper, the combined influences of biotic interactions, environmental components and harvesting strategy on the spread of Hantavirus are investigated. By employing a multi-species model consisting of (susceptible and infected) rodents and alien species, we show that interspecific competition from alien species has an effect in reducing the spread of infection, and this species could be employed as a potential biocontrol agent. Our analysis using numerical continuation and simulation also reveals the conditions under which Hantavirus infection occurs and disappears as the environmental conditions and the intensity of harvesting change. Without harvesting, infection emerges when environments are conducive. Inclusion of moderate harvesting in favourable environments can lead to disappearance of infection among rodent species. However, as the intensity of harvesting increases, this situation can cause extinction of all rodents species and consequently, jeopardise biodiversity. Overall, our results demonstrate how the interplay of different factors can combine to determine the spread of infectious diseases.
Environmental enrichment (EE) is a process of brain stimulation by modifying the surroundings, for example, by changing the sensory, social, or physical conditions. Rodents have been used in such experimental strategies through exposure to diverse physical, social, and exploration conditions. The present study conducted an extensive analysis of the existing literature surrounding the impact of EE on dementia rodent models. The review emphasised the two principal aspects that are very closely related to dementia: cognitive function (learning and memory) as well as psychological factors (anxiety-related behaviours such as phobias and unrealistic worries). Also highlighted were the mechanisms involved in the rodent models of dementia showing EE effects. Two search engines, PubMed and Science Direct, were used for data collection using the following keywords: environmental enrichment, dementia, rodent model, cognitive performance, and anxiety-related behaviour. Fifty-five articles were chosen depending on the criteria for inclusion and exclusion. The rodent models with dementia demonstrated improved learning and memory in the form of hampered inflammatory responses, enhanced neuronal plasticity, and sustained neuronal activity. EE housing also prevented memory impairment through the prevention of amyloid beta (Aβ) seeding formation, an early stage of Aβ plaque formation. The rodents subjected to EE were observed to present increased exploratory activity and exert less anxiety-related behaviour, compared to those in standard housing. However, some studies have proposed that EE intervention through exercise would be too mild to counteract the anxiety-related behaviour and risk assessment behaviour deficits in the Alzheimer's disease rodent model. Future studies should be conducted on old-aged rodents and the duration of EE exposure that would elicit the greatest benefits since the existing studies have been conducted on a range of ages and EE durations. In summary, EE had a considerable effect on dementia rodent models, with the most evident being improved cognitive function.
Neodiplostomum (Conodiplostomum) ramachandrani Betterton, 1976 has been reported from four species of rodent hosts: Echinosorex gymnurus (Raffles): Rattus whiteheadi (Thos); R. muelleri (Jentink) and Callosciurus notatus (Boddaert). A comparison of trematodes recovered from these hosts revealed patterns of host-induced morphological variation taking place. Because N. (Conodiplostomum) ramachandrani shows little generic difference from Fibricola intermedius (Pearson, 1959) Sudarikov, 1960 it is transferred to the genus Fibricola and is now designated Fibricola ramachandrani (Betterton, 1976) Palmieri, Krishnasamy and Sullivan.
Hemoprotozoans are important pathogens of animals and humans, among which some species have zoonotic significance. The prevalence of different hemoprotozoa and Anaplasma spp. in larger mammals have been reported from different regions of the world. But, very few studies have been conducted to estimate the prevalence of hemoprotozoa in rodents and shrews of South-East Asia. The study assessed the prevalence of hemoprotozoa and Anaplasma spp. in rodents and shrews of Bangladesh. Blood samples (n=451) were collected from rodents and shrews between June 2011 and June 2013 and July-December 2015 from 4 land gradients of Bangladesh. Giemsa-stained blood smears revealed that 13% of animals were harboring hemoprotozoa (4.7% Babesia spp., 0.67% Plasmodium spp.), and Anaplasma spp. (7.5%). The study may serve as a guide for future hemoparasitic research of rodents and shrews.
The Asian rodent tick (Ixodes granulatus) occurs throughout much of Asia, it frequently bites humans, and zoonotic pathogens, such as Borrelia burgdorferi (sensu lato) and Rickettsia honei, have been detected within it. Unfortunately, the ecology of I. granulatus remains poorly known, including drivers of its abundance and the interaction ecology with its sylvatic hosts. To elucidate the ecology of this medically important species, the habitat preferences of I. granulatus were assessed in Singapore and Malaysia. Ixodes granulatus showed strong associations with old forest habitats, though across different age classes of old forest there was limited variation in abundance. Ixodes granulatus was absent from other habitats including young forest, scrubland, and parks/gardens. Within its sylvatic rodent hosts, a range of factors were found to be statistically significant predictors of I. granulatus load and/or infestation risk, including sex and body condition index. Male rodents were significantly more likely to be infested and to have higher loads than females, similarly, animals with a lower body condition index were significantly more likely to be infested. Proactive public health efforts targeted at preventing bites by this tick should carefully consider its ecology to minimise ecological overlap between humans and I. granulatus.
Perinatal exposure of Bisphenol A (BPA) to rodents modifies their behavior in later life. To understand how BPA modifies their neurodevelopmental process, we first searched for BPA responsive genes from androgen and estrogen receptor signaling target genes by polymerase chain reaction array in the neonatal male rat brain. We used a transgenic strain of Wistar rats carrying enhanced green fluorescent protein tagged to gonadotropin-inhibitory hormone (GnIH) promoter to investigate the possible interaction of BPA responsive genes and GnIH neurons. We found upregulation of transmembrane protease serine 2 (Tmprss2), an androgen receptor signaling target gene, and downregulation of Forkhead box A1 (Foxa1), an ER signaling target gene, in the medial amygdala of male rats that were subcutaneously administered with BPA from day 1 to 3. Tmprss2-immunoreactive (ir) cells were distributed in the olfactory bulb, cerebral cortex, hippocampus, amygdala, and hypothalamus in 3 days old but not in 1-month-old male rats. Density of Tmprss2-ir cells in the medial amygdala was increased by daily administration of BPA from day 1 to 3. Tmprss2 immunoreactivity was observed in 26.5% of GnIH neurons clustered from the ventral region of the ventromedial hypothalamic nucleus to the dorsal region of the arcuate nucleus of 3-day-old male rat hypothalamus. However, Tmprss2 mRNA expression significantly decreased in the amygdala and hypothalamus of 1-month-old male rats. Foxa1 mRNA expression was higher in the hypothalamus than the amygdala in 3 days old male rats. Intense Foxa1-ir cells were only found in the peduncular part of lateral hypothalamus of 3-day-old male rats. Density of Foxa1-ir cells in the hypothalamus was decreased by daily administration of BPA from day 1 to 3. Foxa1 mRNA expression in the hypothalamus also significantly decreased at 1 month. These results suggest that BPA disturbs the neurodevelopmental process and behavior of rats later in their life by modifying Tmprss2 and Foxa1 expressions in the brain.
Hantaviruses are etiological agents of zoonotic diseases and certain other dis-
eases, which pose a serious threat to human health. When rodent and predator popula-
tions share in an ecology, the competitive force of the populations can lead to a reduction
or elimination of a hantavirus outbreak. The effect of the predator eliminating rodents
and predator populations that tends to reduce or eliminate hantavirus infection is investi-
gated. The existence of several equilibrium points of the model is identified and local and
global stabilities of the model at these equilibrium points are analysed in detail. Numerical
simulations are carried out to illustrate our model results.
The plant Typhonium flagelliforme, commonly known as "rodent tuber" in Malaysia, is often used as a health supplement and traditional remedy for alternative cancer therapies, including leukemia. This study aimed to evaluate in vitro anti-leukemic activity of dichloromethane extract/fraction number 7 (DCM/F7) from T. flagelliforme tuber on human T4 lymphoblastoid (CEMss) cell line. The DCM extract of tuber has been fractionated by column chromatography. The obtained fractions were evaluated for its cytotoxicity toward CEMss cells as well as human primary blood lymphocytes (PBLs). Assessment of apoptosis produced by the most active fraction was evaluated by various microscopic techniques and further confirmation of apoptosis was done by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Phytochemical screening was done by gas chromatography-mass spectrometry (GC-MS). The results shows that 7 out of 12 fractions showed significant cytotoxicity against the selected cell line CEMss, in which fractions DCM/F7, DCM/F11 and DCM/F12 showed exceptional activity with 3, 5 and 6.2 μg ml(-1), respectively. Further studies in the non-cancerous PBL exhibited significant selectivity of DCM/F7 compared to other fractions. Cytological observations showed chromatin condensation, cell shrinkage, abnormalities of cristae, membrane blebbing, cytoplasmic extrusions and formation of apoptotic bodies as confirmed collectively by double-staining of acridine orange (AO)/propidium iodide (PI), SEM and TEM. In addition, DCM/F7 has increased the cellular DNA breaks on treated cells. GC-MS revealed that DCM/F7 contains linoleic acid, hexadecanoic acid and 9-hexadecanoic acid. The present results indicate that T. flagelliforme possess a valuable anti-leukemic effect and was able to produce distinctive morphological features of cell death that corresponds to apoptosis.
The genus Ehrlichia is composed of tick-borne obligate intracellular gram-negative alphaproteobacteria of the family Anaplasmataceae. Ehrlichia includes important pathogens affecting canids (E. canis, E. chaffeensis, and E. ewingii), rodents (E. muris), and ruminants (E. ruminantium). Ehrlichiaminasensis, an Ehrlichia closely related to E. canis, was initially reported in Canada and Brazil. This bacterium has now been reported in Pakistan, Malaysia, China, Ethiopia, South Africa, and the Mediterranean island of Corsica, suggesting that E. minasensis has a wide geographical distribution. Previously, E. minasensis was found to cause clinical ehrlichiosis in an experimentally infected calf. The type strain E. minasensis UFMG-EV was successfully isolated from Rhipicephalus microplus ticks and propagated in the tick embryonic cell line of Ixodes scapularis (IDE8). However, the isolation and propagation of E. minasensis strains from cattle has remained elusive. In this study, the E. minasensis strain Cuiabá was isolated from an eight-month-old male calf of Holstein breed that was naturally infected with the bacterium. The calf presented clinical signs and hematological parameters of bovine ehrlichiosis. The in vitro culture of the agent was established in the canine cell line DH82. Ehrlichial morulae were observed using light and electron microscopy within DH82 cells. Total DNA was extracted, and the full genome of the E. minasensis strain Cuiabá was sequenced. A core-genome-based phylogenetic tree of Ehrlichia spp. and Anaplasma spp. confirmed that E. minasensis is a sister taxa of E. canis. A comparison of functional categories among Ehrlichia showed that E. minasensis has significantly less genes in the 'clustering-based subsystems' category, which includes functionally coupled genes for which the functional attributes are not well understood. Results strongly suggest that E. minasensis is a novel pathogen infecting cattle. The epidemiology of this Ehrlichia deserves further attention because these bacteria could be an overlooked cause of tick-borne bovine ehrlichiosis, with a wide distribution.
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.