Retinol deficiency and Dipetalonema viteae infection in the hamster

Following chronic retinol (vitamin A) deprivation leading to exhaustion of liver vitamin A reserves below 50 I.U. per liver hamsters were fed diets either deficient in ("Rd”: 250 I.U.A/kg in experiment I, 1000 I.U.A/kg in experiment II) or enriched with retinol ("Rw”: 10000 I.U.A/kg in experiment I and II). After 4 weeks some of the animals (36 in experiment I, 30 in II) were infected with 150 3rd-stage larvae of D. viteae, while clean animals were kept as controls. The retinol status, the immune response (indirect fluorescent antibody test: IFAT) and parasitological parameters were examined up to 8 (experiment I) and 12 weeks (experiment II) post infection (p.i.). Rd hamsters had levelling off of weight gain or weight loss, severely deficient retinol levels in serum and liver, and high mortality. Weight gain was less in infected than in uninfected hamsters, and the capacity of infected Rw animals to restore liver retinol was significantly lower than that of uninfected Rw animals. IFAT titres were similar in Rd and in Rw animals, but microfilaraemia was significantly enhanced at 8 and 10·5 weeks p.i. in Rd hamsters. While the number of worms recovered from Rd and Rw hamsters was similar, there was a significant increase in the ratio of female to male worms in Rd hamsters. Rd hamsters in experiment I produced 3·3 times the worm mass per 100 g body-weight than Rw hamsters. Also, the average mass per female worm was significantly higher in Rd than in Rw hamsters, and this parameter was negatively correlated with the liver retinol concentration in experiment I (r=−0·89). Retinol deficiency has a marked effect on growth and fertility of D. viteae in hamster

Toxocariasis: a silent threat with a progressive public health impact

Background: Toxocariasis is a neglected parasitic zoonosis that afflicts millions of the pediatric and adolescent populations worldwide, especially in impoverished communities. This disease is caused by infection with the larvae of Toxocara canis and T. cati, the most ubiquitous intestinal nematode parasite in dogs and cats, respectively. In this article, recent advances in the epidemiology, clinical presentation, diagnosis and pharmacotherapies that have been used in the treatment of toxocariasis are reviewed. Main text: Over the past two decades, we have come far in our understanding of the biology and epidemiology of toxocariasis. However, lack of laboratory infrastructure in some countries, lack of uniform case definitions and limited surveillance infrastructure are some of the challenges that hindered the estimation of global disease burden. Toxocariasis encompasses four clinical forms: visceral, ocular, covert and neural. Incorrect or misdiagnosis of any of these disabling conditions can result in severe health consequences and considerable medical care spending. Fortunately, multiple diagnostic modalities are available, which if effectively used together with the administration of appropriate pharmacologic therapies, can minimize any unnecessary patient morbidity. Conclusions: Although progress has been made in the management of toxocariasis patients, there remains much work to be done. Implementation of new technologies and better understanding of the pathogenesis of toxocariasis can identify new diagnostic biomarkers, which may help in increasing diagnostic accuracy. Also, further clinical research breakthroughs are needed to develop better ways to effectively control and prevent this serious disease

Effect of Sanitation on Soil-Transmitted Helminth Infection: Systematic Review and Meta-Analysis

A systematic review and meta-analysis by Kathrin Ziegelbauer and colleagues finds that sanitation is associated with a reduced risk of transmission of helminthiases to humans

Intestinal parasite prevalence in an area of Ethiopia after implementing the SAFE strategy, enhanced outreach services, and health extension program

The SAFE strategy aims to reduce transmission of Chlamydia trachomatis through antibiotics, improved hygiene, and sanitation. We integrated assessment of intestinal parasites into large-scale trachoma impact surveys to determine whether documented environmental improvements promoted by a trachoma program had collateral impact on intestinal parasites.; We surveyed 99 communities for both trachoma and intestinal parasites (soil-transmitted helminths, Schistosoma mansoni, and intestinal protozoa) in South Gondar, Ethiopia. One child aged 2-15 years per household was randomly selected to provide a stool sample of which about 1 g was fixed in sodium acetate-acetic acid-formalin, concentrated with ether, and examined under a microscope by experienced laboratory technicians.; A total of 2,338 stool specimens were provided, processed, and linked to survey data from 2,657 randomly selected children (88% response). The zonal-level prevalence of Ascaris lumbricoides, hookworm, and Trichuris trichiura was 9.9% (95% confidence interval (CI) 7.2-12.7%), 9.7% (5.9-13.4%), and 2.6% (1.6-3.7%), respectively. The prevalence of S. mansoni was 2.9% (95% CI 0.2-5.5%) but infection was highly focal (range by community from 0-52.4%). The prevalence of any of these helminth infections was 24.2% (95% CI 17.6-30.9%) compared to 48.5% as found in a previous study in 1995 using the Kato-Katz technique. The pathogenic intestinal protozoa Giardia intestinalis and Entamoeba histolytica/E. dispar were found in 23.0% (95% CI 20.3-25.6%) and 11.1% (95% CI 8.9-13.2%) of the surveyed children, respectively. We found statistically significant increases in household latrine ownership, use of an improved water source, access to water, and face washing behavior over the past 7 years.; Improvements in hygiene and sanitation promoted both by the SAFE strategy for trachoma and health extension program combined with preventive chemotherapy during enhanced outreach services are plausible explanations fo the changing patterns of intestinal parasite prevalence. The extent of intestinal protozoa infections suggests poor water quality or unsanitary water collection and storage practices and warrants targeted intervention

Mefloquine tolerability during chemoprophylaxis: focus on adverse event assessments, stereochemistry and compliance

This longitudinal study of travellers to Africa taking mefloquine (MQ) chemoprophylaxis aimed to quantify and assess non-serious adverse events (AE) occurring during short-term prophylaxis and relate these to concentrations of racemic MQ, its enantiomers and metabolite. A total of 420 volunteers (52% F) participated. AEs with some impact on activities were reported by 11.2% of participants including 7.9% of neurological/psychiatric symptoms. Women were more likely to report AEs (P = 0.02). The standardized questionnaires used showed more pathological indicators in travellers who reported subjective AE with significantly more dizziness, distress, sleep disturbances and a high total mood disturbance (TMD) in the AE group. There was, however, no significant performance deficit in computerized psychomotor tests in those experiencing AE. Furthermore, no significant differences were observed in enantiomer ratios, metabolite concentrations, or racemic MQ levels in participants with or without AEs suggesting that these factors are not the main predictors of mefloquine intolerability