Larva migrans in Votuporanga, São Paulo, Brazil: Where does the danger hide?

Soil samples collected near municipal schools (public/EMEI and private/EPEI schools), clubs (CLB), public squares (PS) and residential condominiums (CND) and samples of animal faeces from the Zoonosis Control Centre (CCZ) of the municipality of Votuporanga/SP were analysed using the Baermann method for the detection of zoonotic helminth larvae. The prevalence rates of the nematode genera identified were determined, and the results were compared using Fisher's exact and chi-square frequency tests. Information about cases of larvae migrans in the population were collected from the Family Health Units and the private health plans. All sites were positive for Ancylostoma spp. and, with the exception of EPEIs and dog faeces, for Strongyloides spp. The prevalence of Ancylostoma spp. was 87.5% for CND samples, 74.29% for EMIEs, 63.64% for CLB, 61.76% for PS and 64.29% for dog's and 42.86% for cats at CCZ. The prevalence of Strongyloides spp. ranged from 14.29% (cats/CCZ) to 41.18% (PS). Cases of cutaneous larva migrans were reported during interviews. Thus, from the public health perspective, the risk of individuals that frequent recreational areas in the municipality, especially children, to be infected by helminth larvae is noteworthy, indicating the need to develop policies aimed at controlling this important zoonosis.

Old friends and friendly fire: Pregnancy, hookworm infection, and anemia among tropical horticulturalists.

OBJECTIVES: Despite public health concerns about hookworm infection in pregnancy, little is known about immune profiles associated with hookworm (Necator americanus and Ancylostoma duodenale) infection during pregnancy. Fetal tolerance requirements may constrain maternal immune response to hookworm, thereby increasing susceptibility to new infections or increasing hemoglobin loss. To explore this possibility, we study systemic immune response and hemoglobin levels in a natural fertility population with endemic helminthic infection. METHODS: We used Bayesian multilevel models to analyze mixed longitudinal data on hemoglobin, hookworm infection, reproductive state, eosinophils, and erythrocyte sedimentation rate (ESR) to examine the effects of pregnancy and hookworm infection on nonspecific inflammation, cellular parasite response, and hemoglobin among 612 Tsimane women aged 15-45 (1016 observations). RESULTS: Pregnancy is associated with lower eosinophil counts and lower eosinophil response to hookworm, particularly during the second and third trimesters. Both hookworm and pregnancy are associated with higher ESR, with evidence for an interaction between the two causing further increases in the first trimester. Pregnancy is moderately associated with higher odds of hookworm infection (OR: 1.23, 95% CI: 0.83 to 1.83). Pregnancy and hookworm both decrease hemoglobin and may interact to accentuate this effect in the first-trimester of pregnancy (Interaction: ß: -0.30 g/dL; CI: -0.870 to 0.24). CONCLUSIONS: Our findings are consistent with a possible trade-off between hookworm immunity and successful pregnancy, and with the suggestion that hookworm and pregnancy may have synergistic effects, particularly in the first trimester.

Larva migrans in Votuporanga, São Paulo, Brazil: Where does the danger hide? / Larva migrans em Votuporanga, SP, Brazil: Onde se esconde o perigo?

Abstract Soil samples collected near municipal schools (public/EMEI and private/EPEI schools), clubs (CLB), public squares (PS) and residential condominiums (CND) and samples of animal faeces from the Zoonosis Control Centre (CCZ) of the municipality of Votuporanga/SP were analysed using the Baermann method for the detection of zoonotic helminth larvae. The prevalence rates of the nematode genera identified were determined, and the results were compared using Fisher's exact and chi-square frequency tests. Information about cases of larvae migrans in the population were collected from the Family Health Units and the private health plans. All sites were positive for Ancylostoma spp. and, with the exception of EPEIs and dog faeces, for Strongyloides spp. The prevalence of Ancylostoma spp. was 87.5% for CND samples, 74.29% for EMIEs, 63.64% for CLB, 61.76% for PS and 64.29% for dog's and 42.86% for cats at CCZ. The prevalence of Strongyloides spp. ranged from 14.29% (cats/CCZ) to 41.18% (PS). Cases of cutaneous larva migrans were reported during interviews. Thus, from the public health perspective, the risk of individuals that frequent recreational areas in the municipality, especially children, to be infected by helminth larvae is noteworthy, indicating the need to develop policies aimed at controlling this important zoonosis.

Resumo Amostras de solo colhidas em escolas municipais (ensino público/EMEI e privado/EPEI), clubes (CLB), praças públicas (PP), condomínios residenciais (CND) e de fezes de animais do Centro de Controle de Zoonoses (CCZ) do município de Votuporanga/SP, foram submetidas ao método Baermann para detecção de larvas de helmintos zoonóticos. Foram determinadas as taxas de prevalência dos nematódeos identificados, e os resultados confrontados pelos testes Exato de Fisher e Qui-quadrado. Atendimentos de casos de larvas migrans na população foram levantados em entrevistas realizadas em Unidades de Saúde da Família e em planos de saúde privados. Todos os locais apresentaram positividade para Ancylostoma spp. e, com exceção de EPEIs e de fezes caninas, para Strongyloides spp. Prevalência de Ancylostoma spp. foi verificada em amostras de CNDs (87,50%), EMEIs (74,29%), CLBs (63,64%), PPs (61,76%) e em fezes de cães e gatos do CCZ (64,29% e 42,86%, respectivamente). As prevalências de Strongyloides spp. variaram de 14,29% (gatos/CCZ) a 41,18% (PP). Atendimentos de casos de larva migrans cutânea foram relatados nas entrevistas. Portanto, ressalta-se o risco de frequentadores de áreas de lazer do município, especialmente crianças, de adquirirem infecção por larvas de helmintos, indicando a necessidade da elaboração de propostas de políticas voltadas ao controle dessa importante zoonose.

Hookworm infection aggravates metabolic disorder in obesity.

Obesity and ancylostomiasis are considered public health problems. Recent studies have shown that infection by intestinal helminths in obese individuals can ameliorate metabolic disorder and improve glucose tolerance by decreasing both insulin resistance and low-intensity inflammation. However, few helminth species have been studied in this context, and some modulation mechanisms still require deeper investigation. Therefore, the present work aimed to investigate the role of experimental infection with Ancylostoma ceylanicum in the modulation of the immune response in an obese experimental model. Four groups of hamsters were used as follows: two groups were submitted to a hyperlipidic and hypercaloric diet capable of inducing obesity, one infected and the other uninfected; and two normonourished control groups, one infected and one uninfected by A. ceylanicum. Biochemical, haematological, parasitological and immunological parameters were evaluated. The results demonstrated that A. ceylanicum infection accentuated weight loss in obese animals compared to normonourished animals. However, obesity reduced the recovery of worms and oviposition of the females, and both infected groups showed decreased levels of haemoglobin, albumin, iron and erythrocytes. Significant relations were observed for pathogenesis in the following cases: infection interfered in lipid metabolism, which increased levels of total cholesterol and triglycerides in the obese group, and caused a decrease in HDL levels in both groups. Obesity led to an increase in glucose levels, and the infection exacerbated this parameter in both the normonourished and obese groups. Inflammation was intensified in obese animals that showed elevated macrophage and neutrophil activation in adipose tissue, enlargement of the spleen and accumulation of lipids in the liver and faeces. Despite the decrease in IFN-γ levels, the infection did not potentiated the expression of the Foxp3, IL-10 and IL-2 transcription factor for any of the infected groups, markers that could positively compensate the host from the damage caused by obesity.

The crowding effect in Ancylostoma ceylanicum: density-dependent effects on an experimental model of infection.

This study compared the course of Ancylostoma ceylanicum infection in hamsters infected with different inocula and the consequences for the host and helminth populations. The average of adult worms recovered, according to the number of third stage larva used, were 28.0, 24.8, 24.6, and 24.8% to inocula size of 25 L3, 75 L3, 125 L3, and 250 L3, respectively. The size of the inoculum did not affect the establishment, survival, or fecundity of adult helminths. Reductions in the red blood cell and hemoglobin levels in the infected group were inversely proportional to the number of white blood cells. Moreover, differential cell counting revealed a positive correlation between the worm load and leucocyte numbers. The humoral response against excretion-secretion antigens was more robust and sensitive compared with the response against crude extract, with no direct linear correlation with the number of worms. The effect of the population density was more evident in females.

Parasitological and hematological aspects of co-infection with Angiostrongylus vasorum and Ancylostoma caninum in dogs.

Dogs are frequently infected by one or more species of endoparasites, which can lead to secondary infections that cause high morbidity and death. In this context, 2 nematode species are of veterinary importance: Angiostrongylus vasorum, which is a parasite of the pulmonary artery and right ventricle in domestic and wild canids, and Ancylostoma caninum, which is a parasite of the small intestine in felids and domestic and wild canids. We used 20 mongrel dogs that were divided into groups and infected as follows: Group A included 5 uninfected dogs, Group B included 5 dogs infected with A. vasorum, Group C included 5 dogs infected with A. caninum, and Group D included 5 dogs co-infected with A. vasorum and A. caninum. Parasitological and hematological monitoring were performed. The counts of larvae and eggs shed in the feces varied throughout the collection period. Moreover, negativation was not observed in any of the infected groups. The animals in Group C had macrocytic and hypochromic anemia, whereas the animals in Group D had macrocytic and normochromic anemia. Infected dogs also presented with eosinophilia and lymphocytosis. These data from coproparasitological techniques provide an improved assessment of disease severity and a more thorough understanding of parasitism in the host.

Hookworm products ameliorate dextran sodium sulfate-induced colitis in BALB/c mice.

BACKGROUND: Several lines of evidence have shown that helminthiasis can significantly reduce disease severity in animal models of intestinal inflammation, airway inflammation/hyperreactivity, diabetes, and multiple sclerosis. Identification and characterization of helminth-derived immunomodulatory molecules that contribute to anticolitis effects could lead to new therapeutic approaches in inflammatory bowel diseases (IBDs) without the need for helminth infection. We evaluated the therapeutic potential of adult human hookworm, Ancylostoma ceylanicum, crude (Aw) and excreted/secreted (ES) products on dextran sulfate sodium (DSS)-induced colitis in BALB/c mice. METHODS: Colitis was induced by 5% DSS oral administration for 7 days. Clinical disease severity was monitored daily during concomitant intraperitoneal treatment with helminth-derived products. Additionally, several pathways of immunological modulation induced by A. ceylanicum products (MPO, EPO, Th1, Th2, and Th17 cytokine responses) in the inflamed intestinal microenvironment were assessed. Finally, the histopathological profile of the colon was characterized. RESULTS: Hookworm products are able to modulate the potent proinflammatory response induced by DSS, mainly through the downregulation of Th1 and Th17 cytokines. These proteins also reduce clinical and colonic microscopic inflammation scores as well as EPO and MPO activity. CONCLUSIONS: Ancylostoma ceylanicum Aw and ES mediators have an important therapeutic potential in experimental colitis in mice, which may provide a more socially acceptable form of therapy for patients with IBDs as opposed to using living worms. Our results support the urgency of further isolation and recombinant expression of active hookworm products responsible for the beneficial effects on colitis.

Viability and nematophagous activity of the freeze-dried fungus Arthrobotrys robusta against Ancylostoma spp. infective larvae in dogs.

Viability and in vitro and in vivo activities of freeze-dried conidia of the predatory fungus Arthrobotrys robusta (I-31) were evaluated against infective larvae (L(3)) of Ancylostoma spp. in dogs. A. robusta conidia were lyophilized and stored at 4°C for a month. Freeze-dried conidia were diluted to 1×10(3)conidia/ml and tested in vivo. The treated group consisted of a solution containing conidia (1ml) and 1000 Ancylostoma spp. (L(3)) placed on Petri dishes plated with 2% water-agar (2% WA), at 25°C, in the dark for 10 days. The control group consisted of 1000 Ancylostoma spp. L(3), plated on 2% WA. After 10 days, Ancylostoma spp. L(3) from both the treated and the control groups were recovered and counted. The in vivo test was performed on two dogs by administering a single oral dose of freeze-dried conidia (1.5×10(5)) in aqueous solution to one animal and only water to the other. Fecal samples were collected at 12, 24 and 48h after the treatments, plated 2% WA plates and incubated at 25°C for 15 days. A thousand Ancylostoma spp. L(3) larvae were spread on these plates. At day 15, infective L(3) recovered from the treated and control groups were counted. In the in vitro test, A. robusta was able to survive the freeze-drying process, grow in the plates, form traps and capture Ancylostoma spp. L(3). There was a 75.38% decrease in the number of infective larvae recovered from the treated group. The in vivo test showed that freeze-dried A. robusta conidia survived the passage through the gastrointestinal tract of the treated dog, was able to grow in the plates and capture Ancylostoma spp. L(3), reducing the number of recovered L(3) (p<0.01). Freeze-drying can be an alternative method for conservation of conidia of nematophagous fungi.

Biological control of Ancylostomosis in dogs using the nematode-trapping fungus Monacrosporium thaumasium in southeastern Brazil.

Parasitic nematodes Ancylostoma caninum and Ancylostoma braziliense affect dogs and cats and have great medical and veterinary importance for their high prevalence, zoonotic potential, cosmopolitan characteristic and soil contamination by eggs and larvae. In order to evaluate the efficiency of the nematophagous fungus Monacrosporium thaumasium (isolate NF34a) in the biological control of dog hookworm, 12 adult animals, average weight between 7 and 19 kg, were separated into groups and kept in 2 different kennels: control group (without fungus) and a group treated with 0.5 g of fungal mycelium per kilogram of body weight. The animals were treated and feces samples were collected for egg count (eggs per gram of feces-EPG) and coprocultures during six months, twice a week. Every 15 days soil samples were collected from each group and examined for infective larvae (L(3)) in the period between March and September 2008. From April onwards, EPG and coproculture recordings in the treated group were lower than the control group (p<0.05). Linear regression coefficients for the control group were -30.79 and -160.79 for coproculture and EPG means, respectively. The linear regression coefficients for the treated group were -5.64 and -67.64 for EPG and coproculture means, respectively. Larvae were detected in the soil throughout the experimental period. From June to the end of the experiment (September), means of L(3) recovered from the kennel soil of the control group were higher than the means of the kennel soil of the treated group (p>0.05). The regression coefficient was higher for the treated group (-5.36) than the control group (-1.14), confirming the action of M. thaumasium against larvae in the soil. M. thaumasium can be therefore considered as an alternative environmental control of Ancylostoma spp. in dogs.

Chemoattraction of infective larvae of Ancylostoma braziliense to rodent plasmas and to salts.

Infective larvae of Anyclostoma braziliense were tested for orientational response to rat plasma, to mouse plasma, to rat plasma fractions, and to salts. A high percentage of larvae accumulated at sources of rat plasma, mouse plasma, rat plasma diffusate, concentrated rat plasma dialysate, and some salts, notably sodium chloride. Because sodium chloride is present at an effective concentration in mammalian plasma, and because this salt may form a gradient between the blood and the skin surface, sodium chloride from the blood may direct the penetrating larvae through host's skin. Preliminary tracking of the larvae in gradients of rat plasma and of sodium chloride suggests that orientation to sources of these attractants was via a taxis, possibly a klinotaxis, whereas accumulation at these sources was via a klinokinesis.

Skin penetration of infective hookworm larvae. I. The path of migration of infective larvae of Ancylostoma braziliense in canine skin.

Migratory behaviour of Ancylostoma braziliense was studied in relation to the structure of the skin in dogs after primary infections. Data were obtained studying serial sections of lateral skin areas 6 mm in diameter, which had been exposed to larvae. The sections were stained either with Harris' haematoxylin and eosin or with P.A.S. or as outlined by Crossmon. Most of the larvae managed to penetrate the skin within 1/2 hr after the application. Hairs did not seem to constitute sites of entry. The larvae moved into the horny layer where edges of keratinized cells provide uneven spots. They migrated approximately parallel to the surface from the horny layer into the living epidermis and continued into an external root sheath of a hair follicle. They could only leave this site via sebaceous glands for the dermis or via apocrine sweat glands for the hypodermis. Tunnels from the epidermis into the dermis, however, suggested that a direct trans-epidermal migration had occurred. The vessels invaded by larvae were hypodermal lymphatic vessels. The first ones were found in these structures 1/2 h after the onset of the exposure.

Skin penetration of infective hookworm larvae. II. The path of migration of infective larvae of Ancylostoma braziliense in the metacarpal foot pads of dogs.

The hairless metacarpal foot pads of six hookworm-free puppies were exposed to infective larvae of Ancylostoma braziliense. Serial sections of the biopts stained with Harris' haematoxylin and eosin showed that the infective larvae are able to penetrate the toughest region of canine skin. Pores of eccrine sweat glands did not seem to constitute sites of entry and no larvae were detected in these glands. Larvae were only observed in the epidermis. The histopathology of the infected skin of the foot pads of the puppies was similar to that in human skin with "creeping eruption" as described by Fülleborn (1927). The biopts appeared to consist of hairy skin as well. In the unexposed adjacent hairy skin of the foot pads, larvae were also observed. They were found in the epidermis, hair follicle systems and dermis, suggesting that the migration from the epidermis into deeper tissue depends on the presence of the hair follicle systems.

Skin penetration of infective hookworm larvae. III. Comparative studies on the path of migration of the hookworms Ancylostoma braziliense, Ancylostoma ceylanicum, and Ancylostoma caninum.

The lateral skin areas of nine hookworm-free puppies were exposed to infective larvae of Ancylostoma braziliense, Ancylostoma ceylanicum and Ancylostoma caninum. Serial sections, stained with Harris' haematoxylin and eosin, showed that many similarities exist in the migration patterns of the hookworm species used. However, striking differences were observed between Ancylostoma braziliense on the one hand and Ancylostoma ceylanicum and Ancylostoma caninum on the other hand with regard to the speed with which the penetration occurred. Larvae of Ancylostoma braziliense may travel directly from the epidermis into the dermis--apart from migration via hair follicle systems--a path of migration we did not observe in infections with the other species used. Larvae of Ancylostoma braziliense seem to pass the skin more rapidly than those of Ancylostoma ceylanicum and Ancylostoma caninum. Many larvae of Ancylostoma ceylanicum managed to penetrate the skin 2--6 h after the onset of the exposure.