Zoonotic Gastrointestinal Helminths in Rodent Communities in Southern Guatemala

Rodents are reservoirs and hosts of several pathogens around the world, including zoonotic parasite species. This study aimed to determine the occurrence of zoonotic gastrointestinal helminths in rodents captured inside households in a rural community from southern Guatemala. Sixty-nine rodents were captured in 33% (49/148) of the surveyed households, including Rattus rattus, Rattus norvegicus, Mus musculus, and Sigmodon hispidus. Thirty-six percent (25/69) of these rodents (3 Rattus and 22 Mus musculus), from 45% (22/49) of the households, were parasitized with at least 1 gastrointestinal helminth species. Helminths from 6 species were identified: Hymenolepis diminuta, Moniliformis moniliformis, Heterakis spumosa, Nippostrongylus sp., Strongyloides sp., and Syphacia sp. Two zoonotic species were found in Rattus, H. diminuta in R. rattus (1/6), and M. moniliformis in R. norvegicus (1/1). Coinfection with other non-zoonotic helminth parasites, such as He. spumosa and Strongyloides sp., also was observed in the Rattus genus. Mus musculus had only non-zoonotic helminths: He. spumosa, Nippostrongylus sp., and Syphacia sp. being the most common, and He. spumosa (96%) followed by Nippostrongylus sp. (48%), with a higher presence in males than females, with a similar proportion in adult and young individuals. This is the first report of zoonotic and non-zoonotic helminths parasites in rodents from Guatemala.

Synthesis of controlled size starch nanoparticles (SNPs)

Starch nanoparticles (SNPs) are a promising choice for the strategic development of new renewable and biodegradable nanomaterials for novel biomedical and pharmaceutical applications when loaded with antibiotics or with anticancer agents as target drug delivery systems. The final properties of the SNPs are strongly influenced by the synthesis method and conditions being a controlled and monodispersed size crucial for these applications. The aim of this work was to synthesize controlled size SNPs through nanoprecipitation and microemulsion methods by modifying main operating parameters regarding the effect of amylose and amylopectin ratio in maize starches. SNPs were characterized by size and shape. SNPs from 59 to 118 nm were obtained by the nanoprecipitation method, registering the higer values when surfactant was added to the aqueous phase. Microemulsion method led to 35-147 nm sizes observing a higher particle formation capacity. The composition of the maize used influenced the final particle size and shape.

Viral Diversity, Prey Preference, and Bartonella Prevalence in Desmodus rotundus in Guatemala

Certain bat species serve as natural reservoirs for pathogens in several key viral families including henipa-, lyssa-, corona-, and filoviruses, which may pose serious threats to human health. The Common Vampire Bat (Desmodus rotundus), due to its abundance, sanguivorous feeding habit involving humans and domestic animals, and highly social behavioral ecology, may have an unusually high potential for interspecies disease transmission. Previous studies have investigated rabies dynamics in D. rotundus, yet the diversity of other viruses, bacteria, and other microbes that these bats may carry remains largely unknown. We screened 396 blood, urine, saliva, and fecal samples from D. rotundus captured in Guatemala for 13 viral families and genera. Positive results were found for rhabdovirus, adenovirus, and herpesvirus assays. We also screened these samples for Bartonella spp. and found that 38% of individuals tested positive. To characterize potential for interspecies transmission associated with feeding behavior, we also analyzed cytochrome B sequences from fecal samples to identify prey species and found that domestic cattle (Bos taurus) made up the majority of blood meals. Our findings suggest that the risk of pathogen spillover from Desmodus rotundus, including between domestic animal species, is possible and warrants further investigation to characterize this microbial diversity and expand our understanding of foraging ecology in their populations.

Inhibition of biliary glutathione secretion by cyclosporine A in the rat: possible mechanisms and role in the cholestasis induced by the drug

BACKGROUND/AIMS

Biliary glutathione appears to be a major osmotic factor in the generation of bile acid-independent bile flow. This study was designed to investigate its importance in cyclosporine A-induced cholestasis in both acute and short-term-treated rats.

METHODS

Adult male Wistar rats were treated as follows: (i) with a single i.v. dose of cyclosporine or its vehicle (acute assays); (ii) with cyclosporine, its vehicle or physiological saline, i.p., for 7 days once per day (short-term treatment assays). Bile flow and biliary glutathione levels were determined under anesthesia both before and after intrabiliary hydrolysis of the tripeptide had been inhibited.

RESULTS

Acute cyclosporine administration, at a dose of 20 mg/kg, brought about an abrupt and marked fall in bile flow and bile acid secretion simultaneously with a rapid decrease in the biliary concentration and secretion rates of total, reduced and oxidized glutathione. When the rats were treated with cyclosporine A for 1 week, at a dose of 10 mg/kg per day, similar cholestatic and inhibitory effects on the biliary secretion of glutathione were noted both before and after the intrabiliary catabolism of the tripeptide had been inhibited with acivicin; in addition, the hepatic content of glutathione was also reduced. The cholestatic effect of the drug was associated with reductions in the four bile flow fractions evaluated: bile acid- and glutathione-dependent bile flow and bile acid- and glutathione-independent bile flow.

CONCLUSIONS

These findings indicate that cyclosporine-induced cholestasis in the rat is due not only to alterations in the hepatobiliary transport of bile acids but also to an impairment of bile formation dependent on the biliary secretion of glutathione, possibly through inhibition of the canalicular transport of the tripeptide.

Reversal of cyclosporine A-induced alterations in biliary secretion by S-adenosyl-L-methionine in rats

This study examines the ability of S-adenosyl-L-methionine to prevent or antagonize the cyclosporine A-induced adverse effects on biliary secretion in the rat. S-adenosyl-L-methionine was administered as a single bolus 3, 5 and 8 hr before administering a single dose of cyclosporine A, and also concurrently administered with cyclosporine A for 1 or 2 wk. Acute S-adenosyl-L-methionine preadministration attenuated the cyclosporine-induced cholestasis and inhibition of bile acids, cholesterol and phospholipid biliary secretion. S-adenosyl-L-methionine pretreatment for 1 wk and simultaneous cotreatment with cyclosporine for 1 or 2 wk not only maintained the beneficial effects reported above but further improved them because the adverse effects of the immunosuppressor drug were prevented or antagonized by S-adenosyl-L-methionine. These results provide the first direct evidence of the ability of exogenously administered S-adenosyl-L-methionine to antagonize cyclosporine-induced abnormalities in biliary bile acids, lipids and protein secretion. The beneficial effects of S-adenosyl-L-methionine could be related, at least in part, to the improvement in the hepatobiliary transport of bile acids.

Cyclosporine A hepatotoxicity: effect of prolonged treatment with cyclosporine on biliary lipid secretion in the rat

1. The effects of cyclosporine A (CyA) treatment on liver morphology, bile flow and biliary secretion of bile acid, cholesterol and phospholipid and some plasma biochemical indicators of liver function were examined. 2. Wistar rats were treated i.p. with 10 or 20 mg of CyA/kg per day for 1, 2, 3 or 4 weeks. 3. Treatment increased bile acid and bilirubin plasma concentration. Bile flow and biliary secretion of bile acid, cholesterol and phospholipid were reduced in CyA-treated animals. 4. All these effects of the drug appeared at 1 week after the start of treatment and were enhanced during prolonged treatment. Cyclosporine A-induced cholestasis was due to a decrease in both the bile acid-dependent and -independent fractions of bile flow. 5. The reduction in cholesterol and phospholipid biliary output may be secondary to the inhibition of the hepatobiliary flux of bile acid; however, perturbations in the removal of lipids from the canalicular membrane as well as intracanalicular interaction between CyA and lipid vesicles/micelles could also be involved.