Marta Cecilia Minvielle

Intestinal parasitoses and environmental factors in a rural population of Argentina, 2002-2003

We evaluate the prevalence of intestinal parasites in 504 people and the degree of association between environmental variables and parasites found in population, soil and water in a rural area of Argentina during 2002-2003. A structured survey was used to evaluate the environmental variables and fecal-human, soil and water samples were analyzed. The prevalence of parasites was 45.4%. Most prevalent protozoa were Blastocystis hominis (27.2%) and Giardia lamblia (6.9%), while the most prevalent helminth was Ascaris lumbricoides (3.8%). The analyzed environmental variables showing association (p < 0.05) with presence of parasites in population were: cardboard-tin or wooden house, dirt floor, home or communal water pump, faucet outside the house or public faucet and cesspool or latrine. Parasite forms were found in 82.3% of the soil samples and in 84.2% of the water samples. In both samples we found parasites that were also found in people. In this study we have found deficient sanitary conditions associated with presence of parasites in population and we have evidenced that contaminated soil and water were the source of these parasites.

First genotyping of Giardia lamblia from human and animal feces in Argentina, South America

The purpose of this study was to investigate the genotypes of Giardia lamblia from human and animal feces and their epidemiological and clinical characteristics in Argentina, South America. Seventy isolates, 60 from humans (adults and children), eight from dogs and two from cows were processed by polymerase chain reaction-restriction fragment length polymorphism. Data corresponding to demographic, socio-cultural and environmental variables and presence/absence of signs/symptoms were collected. The triosephosphate isomerase gene was amplified from 43 (71.66%) of the 60 human fecal samples. Among these, 3/43 (6.98%) were genotype AII and 40/43 (93.02%) were genotype B. Assemblage AII was detected in three children who lived together in a shantytown and they were oligosymptomatic and none had diarrhea. This genotype was not found in animals. Genotype B showed a high prevalence in both adults and children. It was also found in polysymptomatic people, many of whom presented diarrhea. It was also found only in one dog. The present study represents the first contribution to the knowledge of G. lamblia genotypes in Argentina.

Related factors to human toxocariasis in a rural community of Argentina

The objective of this study was to evaluate the relationship between toxocariasis frequency and demographic, environmental, sanitary variables, eosinophylia, and other intestinal parasites in a rural population of Argentina. Serological examination of 100 individuals was carried out by using ELISA technique for the detection of anti-toxocara antibodies. Eosinophiles in peripheral blood, presence of intestinal parasites, and demographic, environmental, and socio-cultural data were evaluated. Eighty-one feces samples of dogs belonging to the studied people were analyzed to detect eggs of Toxocara canis. Thirty of them were from 30 dogs and 51 were pools from dog feces. Samples of dirt from around the homes (n: 47) and from public park (n: 4) were taken. To determine the associations, the c(2) and Fisher tests were used. The seroprevalence was 23%. Eosinophilia in peripheral blood was detected in 86.95% seropositive individuals and in 37.66% seronegative individuals (p < 0.001, OR = 11.03). Of the 23 people with positive serology, 69.56% had at least one intestinal parasite. All individuals with positive serology had dogs in their homes. Among the dog owners there was a significant association between the presence of anti-toxocara antibodies and home flooding. Eggs of T. canis were detected in the feces of 5/81 dogs and three of these dogs belonged to individuals with positive serology. Eggs of Toxocara spp. were found in 41.17% of the dirt samples, eight of which came from the area surrounding the homes of individuals with positive serology (p = 0.032; OR = 4.36). Taking into account all the variables influencing the frequency of toxocariasis in this population, the implementation of Public Health programs specifically focused on anti-parasitic treatment of dogs is recommended.

Clinical status and parasitic infection in a Wichí Aboriginal community in Salta, Argentina

In a study, carried out in 2000, of the clinical and parasitological status of a Wichi Aboriginal community living in the suburbs of Tartagal, northern Salta, Argentina, 154 individuals were screened for parasitic infections. Ninety-five faecal samples were also obtained from the same population. Ninety-three percent of the subjects were positive for 1 or more of the parasites investigated by direct test and 70.5% of them had parasitic superinfection. The most frequent helminths were Strongyloides stercoralis (50.5%) and hookworm (47.4%). We found low reinfection rates and a long reinfection period after treatment and provision of safe water and sanitation. Serum reactivity of these patients was analysed by enzyme-linked immunosorbent assay and indirect immunofluorescent assay and 22.1% of them had anti-Toxocara antibodies, 16.2% were positive for a complex antigen of Leishmania braziliensis, 29.9% were positive for a complex Trypanosoma cruzi antigen, and 17.5% were positive for a specific Trypanosoma cruzi antigen, Ag 163B6/cruzipain.

Presencia de parásitos intestinales en paseos públicos urbanos en La Plata, Argentina

With the aim of recovering and identifying parasitic elements we studied soil samples from allpublic place of La Plata, Argentina (urban area). We surveyed 23 places during March and April,2000 and at the time of study we measured both the pH and moisture content of each sample taken.We detected 552 parasitic elements, with 98 corresponding to protozoon cysts, 106 to helmintheggs and 348 to nematode larvae. We conclude that the soils in surveyed public places arecontaminated with parasites of animal as well as human origin.

Biological activity of Paecilomyces genus against Toxocara canis eggs.

Abstract Saprophytic soil fungi can exert ovicidal and ovistatic effects on helminths with differing degrees of efficiency. The representatives of such fungi from temperate regions, Paecilomyces lilacinus (Thom) Samson and P. marquandii (Masse) Hughes, exhibit recognized ovicidal activity on some nematodes. We evaluated the action in vitro of P. lilacinus and P. marquandii on the zoonotic canine roundworm eggs of Toxocara canis. Eggs exposed and unexposed to fungal samples were observed by both light and scanning electron microscopy on days 4, 7 and 14 post-inoculation. Ovicidal activity of P. lilacinus on T. canis eggs was considered to be high and that of P. marquandii to be intermediate.

Oral treatment with a potential probiotic (Enterococcus faecalis CECT 7121) appears to reduce the parasite burden of mice infected with Toxocara canis

Toxocara canis is an intestinal ascarid that is primarily a parasite of dogs. During its mean life-span of 4 months, an adult female To. canis may release up to 200,000 eggs each day. These eggs are excreted by the host and contaminate the environment, where, given adequate temperatures and humidity, they develop into embryonated eggs containing the human-infective second-stage larvae (L2). Humans usually become infected when they ingest the parasite’s eggs, either on contaminated food or as the result of geophagy. Ingested eggs hatch and the larvae spread throughout the body, into the liver, heart, brain and other organs (Minvielle et al., 1999b). The classical syndromes associated with human toxocariasis are visceral larva migrans (VLM), ocular larva migrans (OLM), and covert toxocariasis (www.emedicine.com/ped/ topic2270.htm). Mice can be experimentally infected with To. canis and, since humans and rodents are paratenic hosts for the parasite, serve as a useful model of human toxocariasis (Minvielle et al., 1997, 1999a). The numbers of larvae in the liver and lungs of infected mice peak about 48 h post-infection (Basualdo et al., 1995). Probiotics are traditionally defined as viable but non-pathogenic micro-organisms that, when ingested, have beneficial effects in the prevention and treatment of several enteric diseases (Rolfe, 2000). They have been used successfully in the treatment of several types of parasitic infection, including cryptosporidiosis, giardiasis and trichinellosis (Alak et al., 1999; Bautista-Garfias et al., 2001; Humen et al., 2005). At the Universidad Nacional de La Plata (UNLP), in Argentina, the inhibitory properties and probiotic capacity of Enterococcus strains recovered from natural corn silage (Sparo and Mallo, 2001) are currently under investigation. Among these strains, E. faecalis CECT 7121 is of particular interest since it has been found to have a broad inhibitory spectrum against Gram-positive and Gram-negative bacteria, including bactericidal activity against Listeria monocytogenes and other strains of E. faecalis (Sparo, 2004). Before they are to be used as probiotics or as additives in the biopreservation of food, Enterococcus strains must be carefully checked for virulence factors. Although some Enterococcus strains appear safe, many others are emerging pathogens (Foulquié Moreno et al., 2006). Encouragingly, E. faecalis CECT 7121 shows no signs of known virulence factors, such as haemolysin or gelatinase, or of multiresistance to antibiotics (Sparo et al., 2006). In addition, E. faecalis CECT 7121 caused no detectable lymphocyte proliferation in bio-assays based on murine lymphoid cells and, when tested for intraperitoneal toxicity against BALB/c mice, was found to have a 100fold higher median lethal dose (10 colonyforming units/ml of inoculum) than Enterococcus strains known to cause clinical pathogenicity (Sparo et al., 2006). The main aim of the present study was to determine the effect of oral inoculation with E. faecalis CECT 7121 on the early development of To. canis in experimentally infected mice. Annals of Tropical Medicine & Parasitology, Vol. 101, No. 6, 559–562 (2007)

Participación comunitaria en el control de las parasitosis intestinales en una localidad rural de Argentina

OBJECTIVES To design, implement, and evaluate a complex plan of actions aimed at reducing parasitoses in a rural town in the province of Buenos Aires, Argentina, with the involvement of the community. METHODS The project took place in General Mansilla, Buenos Aires province, in three stages. First, the initial epidemiological situation of intestinal parasitoses in the community was assessed by analyzing for parasites a series of stool samples and anal swabs taken from a sample of 522 individuals. Second, interventions were implemented: the pharmacological treatment of the infected individuals, and health education for the public involving local promoters. Third, the pharmacological treatment was evaluated with followup stool testing for those treated; the health education effort was evaluated through a survey and stool testing for parasites of those who had participated solely in the education. RESULTS The frequency of intestinal parasitoses was 58.2%; of the total, 43.9% were protozoa and 35.2%, helminths. The most common pathogens were Enterobius vermicularis, Blastocystis hominis, and Giardia lamblia. The deworming treatment reduced intestinal parasitoses to 15.1% (P < 0.001), and was more effective in helminths than in protozoa. Intestinal parasitoses declined following the health education intervention, in general (from 58.2% to 47.9%; P = 0.019), as well as for helminths (from 35.2% to 20.3%; P < 0.001), and hygiene habits improved significantly. CONCLUSIONS Treatment of parasitosis and the educational intervention provided by local promoters made it possible to reduce parasitic diseases-particularly those caused by helminths-in the community under study. We recommend extending this experience to other rural communities and broadening the interventions to cutoff additional modes of transmission, such as water and food.

Parasitosis intestinales y su relacion con factores socioeconómicos y condiciones de habitat en niños de Neuquén, Patagonia, Argentina

The prevalence and distribution of intestinal parasites (IP) were investigated in children from twopopulations of different socioeconomic level, located in the same area of the city of Neuquen, inorder to evaluate their relationship with habitat conditions and socioeconomic factors. Serial samplesof faeces and anal scraping of 126 children between 2 and 14 years from two sectors of the suburbanarea of Neuquen (Sector I and Sector II) were analyzed. Data concerning habitat conditions andsocioeconomic parameters were obtained by home visits and an observational structured survey.Presence of IP was detected in 50.7% of children from Sector I (suburban neighborhood with adequatesanitary conditions and middle or middle low socioeconomic level) and in 92.9% from children ofSector II (marginal settlement with poor sanitary conditions and low socioeconomic status). Sevenintestinal protozoan and 4 helminth species were identified.

Biological interaction between soil fungi and Toxocara canis eggs.

Fungi from the soil of public areas in La Plata, Argentina were isolated and evaluated for their biological interaction with Toxocara canis eggs in vitro. We isolated and identified two fungal species: Fusarium pallidoroseum and Mucor hiemalis. Each species was co-cultured with T. canis eggs in sterile distilled water. The samples were observed by light and scanning electron microscopy (SEM) at days 4, 7 and 14 post-inoculation. Under the conditions of our experiments, F. pallidoroseum exhibited a high ovicidal activity on T. canis eggs, whereas M. hiemalis exhibited no such effects.