Insights Into Acute and Delayed Cisplatin-Induced Emesis From a Microelectrode Array, Radiotelemetry and Whole-Body Plethysmography Study of Suncus murinus (House Musk Shrew)

Purpose: Cancer patients receiving cisplatin therapy often experience side-effects such as nausea and emesis, but current anti-emetic regimens are suboptimal. Thus, to enable the development of efficacious anti-emetic treatments, the mechanisms of cisplatin-induced emesis must be determined. We therefore investigated these mechanisms in Suncus murinus, an insectivore that is capable of vomiting.Methods: We used a microelectrode array system to examine the effect of cisplatin on the spatiotemporal properties of slow waves in stomach antrum, duodenum, ileum and colon tissues isolated from S. murinus. In addition, we used a multi-wire radiotelemetry system to record conscious animals’ gastric myoelectric activity, core body temperature, blood pressure (BP) and heart rate viability over 96-h periods. Furthermore, we used whole-body plethysmography to simultaneously monitor animals’ respiratory activity. At the end of in vivo experiments, the stomach antrum was collected and immunohistochemistry was performed to identify c-Kit and cluster of differentiation 45 (CD45)-positive cells.Results: Our acute in vitro studies revealed that cisplatin (1–10 μM) treatment had acute region-dependent effects on pacemaking activity along the gastrointestinal tract, such that the stomach and colon responded oppositely to the duodenum and ileum. S. murinus treated with cisplatin for 90 min had a significantly lower dominant frequency (DF) in the ileum and a longer waveform period in the ileum and colon. Our 96-h recordings showed that cisplatin inhibited food and water intake and caused weight loss during the early and delayed phases. Moreover, cisplatin decreased the DF, increased the percentage power of bradygastria, and evoked a hypothermic response during the acute and delayed phases. Reductions in BP and respiratory rate were also observed. Finally, we demonstrated that treatment with cisplatin caused inflammation in the antrum of the stomach and reduced the density of the interstitial cells of Cajal (ICC).Conclusion: These studies indicate that cisplatin treatment of S. murinus disrupted ICC networking and viability and also affected general homeostatic mechanisms of the cardiovascular system and gastrointestinal tract. The effect on the gastrointestinal tract appeared to be region-specific. Further investigations are required to comprehensively understand these mechanistic effects of cisplatin and their relationship to emesis.

Effectiveness of snap traps on capturing rodent and small mammals in rural area of two provinces (Yogyakarta and West Java) in Indonesia

The study was conducted to determine the effectiveness of snap traps on capturing the rodents and small mammals in two provinces (Yogyakarta and West Java). A small rural area surrounded by large scale ricecrops which indicate rodent damage seasonally was selected as the study site. The trappings were executed during the period of November 2018 – August 2020. Consecutive trappings were performed in two regions using snap traps baited with fresh salty fish and roasted coconut. Around 40-65 traps were set in West Java study sites and 60-65 traps in Yogyakarta for every single trap night, respectively. We checked the captured animals in the early morning and collected them for identification and sexing. In the late afternoon we continued with cleaning of the traps and put in the new same type of bait. A total of 517 animals were obtained with the proportion of the two sexes was almost the same (45.45% males:54.40% females). Based on the physical characteristics, those captured animals were three rodent species (Rattus argentiventer, Rattus tanezumi, Bandicota indica) and one species of insectivore (Suncus murinus). Regarding trapping rate of success, Yogyakarta denoted average values (21.38% in the first trapping and 26.04% from the second trapping) compared to West Java which was only accounted for half of them (11.31% and 11.24% from the first and second trapping, respectively). The heterogeneous habitat configuration probably allowed this situation to occur in Yogyakarta. Moreover, rodent control activities in West Java were implemented more intensively compared to Yogyakarta.

Distribution pattern of chigger mites in south Tamil Nadu, India

Chiggers, the larval Trombiculid mites are the vectors for scrub typhus. Rodents and shrews are the preferred host. Study made at different habitats of chiggers collected in rodents and shrews, revealed more number to Rattus rattus 95(63%) and Suncus murinus 33(22%). Rattus rattus 31(54%) and Suncus murinus 17(30%) alone contributed more in chigger positivity. Chigger mites belonged to eight species under five genera. Leptotrombidium deliense (66%), Schoengatiella ligula (15%), and other chiggers (9%) were collected from 57 positive rodents. Seasonally, there was a significant difference in rodent positivity, and there was no significant difference in the number of chiggers collected. The study indicated the prevalence of chiggers in the various hosts and their variation in rodent/shrew hosts. R. rattus 31(54%) and S. murinus 17(30%) contributed more in chiggers infestation and seasonally wet-cool months favored more chiggers and host positivity from different habitats.

Molecular detection and genetic characterization of Wenzhou virus in rodents in Guangzhou, China

Background Wenzhou virus (WENV), a newly discovered mammarenavirus in rodents, is associated with fever and respiratory symptoms in humans. This study was aimed to detect and characterize the emerging virus in rodents in Guangzhou, China. Results A total of 100 small mammals, including 70 Rattus norvegicus, 22 Suncus murinus, 4 Bandicota indica, 3 Rattus flavipectus, and 1 Rattus losea, were captured in Guangzhou, and their brain tissues were collected and pooled for metagenomic analysis, which generated several contigs targeting the genome of WENV. Two R. norvegicus (2.9%) were further confirmed to be infected with WENV by RT-PCR. The complete genome (RnGZ37-2018 and RnGZ40-2018) shared 85.1–88.9% nt and 83.2–96.3% aa sequence identities to the Cambodian strains that have been shown to be associated with human disease. Phylogenetic analysis showed that all identified WENV could be grouped into four different lineages, and the two Guangzhou strains formed an independent clade. We also analyzed the potential recombinant events occurring in WENV strains. Conclusions Our study showed a high genetic diversity of WENV strains in China, emphasizing the relevance of surveillance of this emerging mammarenavirus in both natural reservoirs and humans.

Effects of Brain Size on Adult Neurogenesis in Shrews

Shrews are small animals found in many different habitats. Like other mammals, adult neurogenesis occurs in the subventricular zone of the lateral ventricle (SVZ) and the dentate gyrus (DG) of the hippocampal formation. We asked whether the number of new generated cells in shrews depends on their brain size. We examined Crocidura russula and Neomys fodiens, weighing 10–22 g, and Crocidura olivieri and Suncus murinus that weigh three times more. We found that the density of proliferated cells in the SVZ was approximately at the same level in all species. These cells migrated from the SVZ through the rostral migratory stream to the olfactory bulb (OB). In this pathway, a low level of neurogenesis occurred in C. olivieri compared to three other species of shrews. In the DG, the rate of adult neurogenesis was regulated differently. Specifically, the lowest density of newly generated neurons was observed in C. russula, which had a substantial number of new neurons in the OB compared with C. olivieri. We suggest that the number of newly generated neurons in an adult shrew’s brain is independent of the brain size, and molecular mechanisms of neurogenesis appeared to be different in two neurogenic structures.

First Detection of Bartonella spp. in Small Mammals from Rice Storage and Processing Facilities in Myanmar and Sri Lanka

(1) Background: Bartonella spp. are zoonotic bacteria with small mammals as main reservoirs. Bartonella spp. prevalence in small mammals from Myanmar and Sri Lanka are yet unknown. (2) Methods: Small mammals were snap trapped in Sri Lanka and Myanmar in urban surroundings. Spleens-derived DNA was screened for Bartonella spp. using conventional PCR based on three target genes. Positive samples were sequenced. (3) Results: 994 small mammals were collected comprising 6 species: Bandicota bengalensis, Bandicota indica, Rattus exulans, Rattus rattus, Mus booduga, and Suncus murinus. In Myanmar, the Bartonella prevalence in Bandicoot rats (68.47%) was higher than in Rattus rattus (41.67%), Rattus exulans (21.33%), and Suncus murinus (3.64%). Furthermore the prevalence in Myanmar (34%, n = 495) was twice as high as in Sri Lanka (16%, n = 499). In Sri Lanka, Bartonella spp. occurred almost exclusively in R. rattus. In Myanmar, Bartonella kosoyi was mainly detected (56%), followed by Bartonella sp. KM2529 (15%), Bartonella sp. SE-Bart D (12%) and Bartonella henselae (1%). In Sri Lanka, B. phoceensis (60%) and Bartonella sp. KM2581 (33%) were predominant. (4) Conclusions: Bartonella spp. were detected in all investigated small mammal species from Myanmar and Sri Lanka for the first time. Bartonella kosoyi and B. henselae are zoonotic. As these small mammals originated from urban settlements, human bartonellosis seems likely to occur.

Diversity of Rodent Species and Its Potency as the Vector for Transmitting Rodent Borne Parasitic Disease in Households

Rodent species have been known as the major pest in the agricultural sector leading to economic losses. They are also identified as the vector for several rodent -borne zoonotic diseases. However, a specific study on observing their diversity in households closed to lowland irrigated agroecosystems that correspond to disease distribution’s role is limited. To address this issue, a field study was performed during the 2019 -2020 cropping season in two sites (Yogyakarta and West Java) which were categorized as the rice production centers. Trapping was conducted consecutively for 13-30 days using 65-75 snap traps. Roasted coconut and salty fish were used to attract rodents. In West Java, 3 rodent species ( Rattus argentiventer, Rattus tanezumi, Bandicota indica) and insectivore small mammal (Suncus murinus) were discovered from 1,950 trap nights. Meanwhile, the setting of 900 trap nights in Yogyakarta indicated less diverse rodents with only one species (Rattus tanezumi) and the same insectivore discovered. All captured animals were dissected and observed for the endoparasites. We obtained two potent species of parasites ( Taenia taeniaeformis and Capillaria hepatica), which can be transmitted by rodents to the local people if they do not apply a proper health practice.