Parasite survey in mouse and rat colonies of Brazilian laboratory animal houses kept under differents sanitary barrier conditions

Parasites and Parasitic Diseases of Laboratory Animals in Plateau State Nigeria: The zoonotic implications

Parasitic agents in laboratory animals, are detrimental to the success of researches and can also infect personnel and researchers. This study is aimed at investigating the parasitic infections of laboratory animals maintained in animal houses of The National Veterinary Research Institute, Vom, Nigeria, as well as determining the zoonotic implications of these parasites. Two hundred and six laboratory animals (72 rabbits, 55 guinea pigs, 50 mice and 29 rats) were randomly sampled. Faecal samples and skin scrapings were collected and subjected to parasitological analyses. Pathological examinations were conducted on laboratory animals that had skin lesions. Sixteen different species comprising of 7 nematodes, 5 cestodes, 3 protozoans, and 1 mite were detected. Eimeria species (40/206; 19.42%; 95% CI = 14.44-25.25) was the most prevalent parasite, followed by Syphacia muris (26/206; 12.62%; 95% CI = 8.59-17.69). Entamoeba caviae, Tritrichomonas caviae, Rodentolepis microstoma, Rodentolepis nana, Heterakis spumosa, Capillaria hepatica and Cysticercus fasciolaris were the least prevalent with a 0.49% prevalence each. Three, four, five and six different species of parasites were detected in mice, guinea pigs, rats and rabbits respectively. The Chi-Square analysis revealed that the infection rate of parasites was significantly higher (p =  < 0.01) in mice compared to rats, rabbits and guinea pigs. Of the Sixteen species of parasites detected, Eimeria species, Syphacia muris, Rodentolepis diminuta, Rodentolepis microstoma, Rodentolepis nana, and Capillaria hepatica are zoonotic. This study showed that 40.29% of the studied laboratory animals were infected with one parasite species or the other. The outcome of this study stresses the zoonotic implications of the parasites detected. We thereby advise researchers and handlers to take caution and apply utmost sanitary measures in the handling of laboratory animals so as to prevent themselves from being infected with these zoonotic parasites.

Comparative Comprehensive Analysis on Natural Infections of Hymenolepis Diminuta and Hymenolepis Nana in Commensal Rodents

This first comprehensive report from Punjab province of India relates to patho-physiological alterations alongwith morpho-molecular characterisation and risk assessment of natural infections of Hymenolepis diminuta and Hymenolepis nana in 291commensal rodents including house rat, Rattus rattus (n=201) and lesser bandicoot rat, Bandicota bangalensis (n=90). Small intestine of 53.61 and 64.95 % rats was found infected with H. diminuta and H. nana, respectively with a concurrent infection rate of 50.86 %. There was no association between male and female rats and H. diminuta and H. nana infections (ᵡ² = 0.016 and 0.08, respectively, d.f.= 1, P>0.05), while the host age had significant effect on prevalence of H. diminuta and H. nana (ᵡ² = 28.12 and 7.18, respectively, d.f.= 1, P≤0.05) infection. Examination of faecal samples and intestinal contents revealed globular shaped eggs of H. diminuta without polar filaments (76.50 ± 3.01μm x 67.62 ± 2.42 μm), while smaller sized oval eggs of H. nana were with 4 – 8 polar filaments (47.87 ± 1.95 μm x 36.12 ± 3.05 μm). Cestode infection caused enteritis, sloughing of intestinal mucosa, necrosis of villi and inflammatory reaction with infiltration of mononuclear cells in the mucosa and submucosa. Morphometric identification of the adult cestodes recovered from the intestinal lumen was confirmed by molecular characterisation based on nuclear ITS-2 loci which showed a single band of 269 bp and 242 bp for H. diminuta and H. nana, respectively. Pairwise alignment of the ITS-2 regions showed 99.46 % similarity with sequences of H. diminuta from USA and 100 % similarity with sequences of H. nana from Slovakia, Kosice.

Useful properties of undifferentiated mesenchymal stromal cells and adipose tissue as the source in liver-regenerative therapy studied in an animal model of severe acute fulminant hepatitis

BACKGROUND AIMS

End-stage liver diseases frequently require liver transplantation. Cell therapy could be an alternative. This study aimed to analyze whether undifferentiated mesenchymal stromal cells (U-MSCs) or MSC-derived hepatocyte-like cells (DHLCs) from adipose tissue (AT), umbilical cord blood (UCB) and bone marrow (BM) would better restore damaged liver.

METHODS

AT was obtained from lipo-aspiration, UCB from an Umbilical Cord Blood Bank and BM from a BM Transplantation Unit. AT (collagenase digestion), UCB and BM (Ficoll gradient) were cultured (Dulbecco's modified Eagle's medium, low glucose, FBS) for 3 days. Detached adherent cells, at passage 4, were characterized as MSCs. Genetic stability was investigated by means of telomerase enzyme activity and karyotype. Hepatocyte differentiation protocol was performed with the use of Dulbecco's modified Eagle's medium, hepatocyte growth factor, basic fibroblast growth factor and nicotinamide (7 days); maturation medium (oncostatin, dexamethasone, insulin, transferrin and selenium) was added at 36 days. Hepatogenesis analyses were performed by use of morphology and albumin, AF, tyrosine-aminotransferase and glutamine synthetase gene expression and quantitative reverse transcription-polymerase chain reaction on days 9, 18, 25 and 36. Functionality was assessed through glycogen storage detection, indocyanine green absorption and transplantation procedure. U-MSCs and DHLCs were injected 48 h after induced fulminant hepatitis (intraperitoneal injection of carbon tetrachloride) in SCID/BALB-c mice. Histopathologic analyses were performed on days 7 and 15. Human origin included albumin and CK19 human markers.

RESULTS

All MSCs differentiated into functional hepatocyte-like cells, stored glycogen and absorbed indocyanine green. AT-MSC DHLC gene expression was more consistent with a normal hepatogenic-differentiation profile. UCB-MSCs expanded weakly, impairing their use for the transplantation procedure. AT and BM U-MSCs and DHLCs regenerated liver injury equally. Regenerated hepatocytes exhibited human origin.

CONCLUSIONS

AT might be the source and U-MSCS the stem cells useful for liver-regenerative therapy.

Diagnosis of the pinworm Syphacia muris in the Wistar rat Rattus norvegicus

This study aimed to compare three qualitative parasitological methods for the diagnosis of Syphacia muris infection in 30 Wistar rats (Rattus norvegicus) infected naturally. Methods of spontaneous sedimentation (Hoffman, Pons and Janer, or HPJ) and spontaneous flotation (Willis) for faecal samples and a method of taping (Graham) were performed and compared. The Graham and Willis methods were more sensitive than the HPJ method (P< 0.05). The Graham method was able to detect S. muris eggs in 100% of the samples. Eggs were detected in 83% and 60% of the samples using the Willis and HPJ methods, respectively. Method choice is important for screening for parasites of rats kept under laboratory conditions, as accurate diagnosis helps prevent future environmental contamination and infection. We concluded that the Graham method was the most efficient of those tested in this study for detection of S. muris infection in rats. This method is also rapid, inexpensive and practical, and should be implemented as a necessary measure for infection control.

Faecal examination and PCR to detect Strongyloides venezuelensis in experimentally infected Lewis rats

More sensitive methodologies are necessary to improve strongyloidiasis diagnosis. This study compared the sensitivities of the McMaster modified technique and polymerase chain reaction (PCR) assays, both performed in faecal samples. Lewis rats were subcutaneously infected with 4,000, 400 or 40 infective third-stage larvae, considered as high, moderate or low infection, respectively. Seven days later, they were euthanized to count adult nematodes recovered from the small intestine. Stool samples were used to count the number of eggs per gram (EPG) of faeces and to detect parasite DNA by PCR performed with a species and a genus primer pair. The sensitivity of these assays depended upon parasite burden and the primer specificity. All assays presented 100% sensitivity at the highest parasite load. In the moderate infection, EPG and PCR with the genus primer maintained 100% specificity, whereas PCR sensitivity with the species primer decreased to 77.7%. In low infection, the sensitivity was 60% for EPG, 0% for PCR with the species primer and 90% for PCR done with the genus primer. Together, these results suggest that PCR with a genus primer can be a very sensitive methodology to detect Strongyloides venezuelensisin faeces of Lewis rats infected with very low parasite burden.

Sanitary profile in mice and rat colonies in laboratory animal houses in Minas Gerais: I - Endo and ectoparasites

The sanitary conditions of 13 animal houses in nine public institutions in Minas Gerais, and the presence of endo and ectoparasites of mice and rats colonies kept in these facilities were evaluated. Data about barriers to prevent the transmission of diseases and a program of sanitary monitoring were obtained through a questionnaire and local visit. Parasitological methods were performed for diagnosing mite, lice, helminthes, and protozoa parasites in 344 mice and 111 rats. Data have shown that the majority of the animal houses had neither proper physical environment nor protection barriers to prevent the transmission of infections. Parasitological results have shown that only one animal house (7.7%) had parasite free animals, whereas the others have presented infected animals and the prevalences of parasites in the mice colonies were: Myobia musculi (23.1%); Myocoptes musculinus (38.5%); Radfordia affinis (15.4%); Syphacia obvelata (92.3%); Aspiculuris tetraptera (23.1%); Hymenolepis nana (15.4%); Spironucleus muris (46.2%); Giardia muris (46.2%); Tritrichomonas muris (53.8%); Trichomonas minuta (61.5%); Hexamastix muris (7.7%); and Entamoeba muris (84.6%). As for the rat colonies, the prevalences were: Poliplax spinulosa (8.1%); Syphacia muris (46.2%); Trichosomoides crassicauda (28.6%); Spironucleus muris (85.7%); Tritrichomonas muris (85.7%); Trichomonas minuta (85.7%); Hexamastix muris (14.3%) and Entamoeba muris (85.7%).