Risk factors and prevalence of enteroparasitic diseases in shellfish pickers from a lake area in the Northeast of Brazil / Fatores de risco e prevalência de enteroparasitoses em marisqueiras de uma região lagunar no Nordeste do Brasil

INTRODUCTION: Intestinal parasitosis are a public health problem worldwide. There are several risk factors and a high association with some specific labor activities. OBJECTIVE: The present study assessed the risk factors and prevalence of enteroparasitic diseases in shellfish pickers from one district of Maceió, Alagoas state, Brazil. METHODS: Crosssectional study of 41 female shellfish pickers including parasitological tests in fecal samples and a questionnaire with objective and subjective questions. Sand samples from their working environment were also analyzed. RESULTS: At least one species of parasite was found in 19.51% of the fecal samples. Pathogenic species of Giardia lamblia, Trichuris trichiura, Schistosoma mansoni, Ascaris lumbricoides, Enterobius vermicularis, from the Ancylostomatidae family, and non-pathogenic species of Entamoeba coli were found. Polyparasitism was diagnosed in 37.5% of the positive samples. A total of 57.14% of sand samples contained hookworm larvae. Regarding the risk factor, low educational level was statistically associated to the presence of parasites (p<0.05). CONCLUSION: Greater investment in basic education is needed to increase the knowledge about preventive measures against parasitic diseases and the promotion food-handling courses in order to change existing inadequate habits in the community. Basic sanitation is also essential in preventing environmental contamination.

INTRODUÇÃO: As parasitoses intestinais representam um problema de saúde pública mundial. Estão associados inúmeros fatores de risco, bem como atividades laborais específicas. OBJETIVO: O presente estudo avaliou os fatores de risco e a prevalência de enteroparasitoses em marisqueiras de um bairro da cidade de Maceió, Alagoas, Brasil. MÉTODOS: Procedeu-se um estudo de corte transversal, sendo 41 marisqueiras avaliadas mediante exame parasitológico de fezes e questionário contendo questões discursivas e de múltipla escolha. Foram analisadas também amostras de areia do ambiente de trabalho das mesmas. RESULTADOS: A positividade para pelo menos uma espécie de parasito nas fezes foi de 19,51%. Foram encontradas as espécies patogênicas Giardia lamblia, Trichuris trichiura, Schistosoma mansoni, Ascaris lumbricoides, Enterobius vermicularis e da família Ancylostomatidae, e a espécie não patogênica, Entamoeba coli. Poliparasitismo foi diagnosticado em 37,5% dos exames positivos. Um total de 57,14% das amostras de areia continha larvas de ancilostomatídeos. Em relação aos fatores de risco, a baixa escolaridade foi estatisticamente associada à presença de parasitas (p<0,05). CONCLUSÃO: É necessário maior investimento na educação básica para aprimorar o conhecimento das formas de prevenção das parasitoses e a promoção de cursos de boas práticas de manipulação de alimentos, a fim de modificar hábitos errôneos já incorporados na comunidade. O saneamento básico também é fundamental para evitar contaminação ambiental.

Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia / Parasitos na ostra-do-mangue Crassostrea rhizophorae cultivada no estuário do rio Graciosa em Taperoá, Bahia

In this work, parasites associated with the mangrove oyster Crassostrea rhizophorae were studied at a cultivation unit in the estuary of the Graciosa River in Taperoá, Bahia. On a monthly basis, between April 2011 and March 2012, 20 oysters were collected, measured and fixed in 10% formaldehyde. In order to identify the parasites, routine histological techniques were used. The specimens were embedded in paraffin and sections, 7 µm thick, were cut. These were then stained with Harris hematoxylin and eosin and were examined using an optical microscope. The parameters analyzed to investigate water quality showed that the temperature ranged from 23.9 °C to 29.3 °C, water salinity from 0.4 to 24.2 Practical Salinity Units PSU and recorded rainfall from 80 mm to 406.4 mm/month. During the parasitological analyses, infestation of the polychaete Neanthes succinea was observed in 41% of the oysters. Through histological techniques, the following parasites were identified: colonies of Rickettsia-like organisms (RLOs); the protozoa Nematopsis sp. and Ancistrocoma sp.; the turbellarian Urastoma sp.; the metacestode Tylocephalum sp. and an unidentified tapeworm. The data collected showed that there was low-intensity infection with and prevalence of parasites, except for Nematopsis sp., thus attesting that these cultivated oysters were in a healthy condition.

No presente trabalho, parasitos associados à ostra-do-mangue Crassostrea rhizophorae foram estudados em uma unidade de cultivo no estuário do rio Graciosa em Taperoá, Bahia. Mensalmente, entre abril de 2011 e março de 2012, 20 ostras foram coletadas, mensuradas e fixadas em formol a 10%. Para a identificação dos parasitos, foram utilizadas técnicas histológicas de rotina, com inclusão em parafina e obtenção de cortes com 7µm, corados com hematoxilina de Harris e eosina e examinados em microscopia de luz. Os parâmetros analisados para a qualidade da água mostraram que a temperatura variou de 23,9 °C a 29,3 °C, a salinidade de 0,4 a 24,2 PSU e a pluviometria de 80 mm a 406,4 mm/mês. Nas análises parasitológicas foram observadas infestações do poliqueta Neanthes succinea em 41% das ostras. A partir das técnicas histológicas foram identificados os seguintes parasitos: colônias de organismos assemelhados a Rickettsiae (RLOs); os protozoários Nematopsis sp. e Ancistrocoma sp.; o turbelário Urastoma sp.; o metacestóide Tylocephalum sp. e um platelminto não identificado. Os dados obtidos mostraram baixa intensidade de infecção e prevalência de parasitos, exceto para Nematopsis sp., atestando a boa condição de saúde das ostras no cultivo.

Molecular Variation in the Paragonimus heterotremus Complex in Thailand and Myanmar

Paragonimiasis is an important food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. Of the 7 members of the genus known in Thailand until recently, only P. heterotremus has been confirmed as causing human disease. An 8th species, P. pseudoheterotremus, has recently been proposed from Thailand, and has been found in humans. Molecular data place this species as a sister species to P. heterotremus, and it is likely that P. pseudoheterotremus is not specifically distinct from P. heterotremus. In this study, we collected metacercariae of both nominal species (identification based on metacercarial morphology) from freshwater crabs from Phetchabun Province in northern Thailand, Saraburi Province in central Thailand, and Surat Thani Province in southern Thailand. In addition, we purchased freshwater crabs imported from Myanmar at Myawaddy Province, western Thailand, close to the Myanmar-Thailand border. The DNAs extracted from excysted metacercariae were PCR-amplified and sequenced for ITS2 and cox1 genes. The ITS2 sequences were nearly identical among all samples (99-100%). Phylogenies inferred from all available partial cox1 sequences contained several clusters. Sequences from Indian P. heterotremus formed a sister group to sequences from P. pseudoheterotremus-type metacercariae. Sequences of P. heterotremus from Thailand, Vietnam, and China formed a separate distinct clade. One metacercaria from Phitsanulok Province was distinct from all others. There is clearly considerable genetic variation in the P. heterotremus complex in Thailand and the form referred to as P. pseudoheterotremus is widely distributed in Thailand and the Thai-Myanmar border region.

Paragonimus and Paragonimiasis in Vietnam: an Update

Paragonimiasis is a food-borne parasitic zoonosis caused by infection with lung flukes of the genus Paragonimus. In Vietnam, research on Paragonimus and paragonimiasis has been conducted in northern and central regions of the country. Using a combination of morphological and molecular methods, 7 Paragonimus species, namely P. heterotremus, P. westermani, P. skrjabini, P. vietnamensis, P. proliferus, P. bangkokenis and P. harinasutai, have been identified in Vietnam. Of these, the first 3, P. heterotremus, P. westermani and P. skrjabini, are known to infect humans in other countries. However, in Vietnam, only P. heterotremus, found in some northern provinces, has been shown to infect humans. Even nowadays, local people in some northern provinces, such as Lai Chau and Yen Bai, are still suffering from P. heterotremus infection. In some provinces of central Vietnam, the prevalence and infection intensity of P. westermani metacercariae in freshwater crabs (the second intermediate hosts) are extremely high, but human cases have not been reported. Likewise, although P. skrjabini was found in Thanh Hoa Province, its pathogenicity to humans in Vietnam still remains uncertain. The results of molecular phylogenetic analyses of Vietnamese Paragonimus species provides new insights on the phylogeny and taxonomy of the genus Paragonimus. Comprehensive molecular epidemiological and geobiological studies on the genus in Vietnam and adjacent countries are needed to clarify the biodiversity and public health significance of the lung flukes.

A Case of Pulmonary Paragonimiasis with Involvement of the Abdominal Muscle in a 9-Year-Old Girl

In Korea, many people enjoy eating raw or underkooked freshwater crayfish and crabs which unfortunately may cause paragonimiasis. Here, we describe a case of pulmonary and abdominal paragonimiasis in a 9-year-old girl, who presented with a 1-month history of abdominal pain, especially in the right flank and the right inguinal area, with anorexia. A chest radiograph revealed pleural effusion in both lungs, and her abdominal sonography indicated an inflammatory lesion in the right psoas muscle. Peripheral blood analysis of the patient showed hypereosinophilia (66.0%) and an elevated total serum IgE level (>2,500 IU/ml). The pleural effusion tested by ELISA were also positive for antibodies against paragonimiasis. Her dietary history stated that she had ingested raw freshwater crab, 4 months previously. The diagnosis was pulmonary paragonimiasis accompanied by abdominal muscle involvement. She was improved after 5 cycles of praziquantel treatment and 2 times of pleural effusion drainage. In conclusion, herein, we report a case of pulmonary and abdominal paragonimiasis in a girl who presented with abdominal pain and tenderness in the inguinal area.

Indochinamon ou (Crustacea: Potamidae) as a New Second Intermediate Host for Paragonimus harinasutai in Luang Prabang Province, Lao PDR

Paragonimus harinasutai metacercariae were found in a species of freshwater crab, Indochinamon ou, collected in a small stream of Namback District, Luang Prabang Province, Lao PDR. Adult flukes were recovered after experimental infection of the metacercariae to dogs. Metacercariae were round or slightly elliptical, 0.666 x 0.626 mm in average size, and had a thin cyst wall of about 20 microm in thickness, a black excretory bladder, convoluted ceca, and some pinkish materials in the body. Adults were somewhat elongated, 95.2 x 36.5 mm in average size, covered with single-tipped tegumental spines, had a smaller oral sucker than the ventral sucker, a moderately branched ovary, and 5-6 lobulated testes. Eggs were ovoid and bilaterally symmetrical in shape, 79 x 45 microm in average size, and had a uniformly thickened shell. By the present study, it has been confirmed that I. ou is a new second intermediate host for P. harinasutai.

Paragonimiasis prevalences in Saraburi Province, Thailand, measured 20 years apart.

Saraburi Province, Central Thailand has been a paragonimiasis-endemic area since 1956. This study compared the prevalences of human paragonimiasis in two villages near Chet Khot Waterfall, Kaeng Khoi District, investigated in 1984-1985 and 2005. The results from the 1980s showed 6.3% and 1% of villagers were positive for Paragonimus eggs in sputum and stool, respectively. In 2005, Paragonimus eggs were not found in feces or sputum. An IgG-ELISA for paragonimiasis was conducted on 33 serum samples collected in the 1980s, 23 collected in 2005 and 25 diagnosed with other parasitic infections. Ninety percent of the samples from the eighties were positive for paragoimiasis, and 43% from 2005 were positive, equivalent to 10.9% and 4.9% of the total population examined in the 1980s and 2005, respectively. Serodiagnosis is currently the best method for detecting paragonimiasis. The positive cases in the 1980s were age 10-60 years and in 2005 were age 34- 67-years-old. The prevalence and intensity of Paragonimus metacercariae in fresh Waterfall crabs collected from Chet Khot Waterfall were significantly lower in the 1980s than in 2005. The prevalence of paragonimiasis in this endemic area has decreased to the level that no egg-producing cases were detected. No infections were found in villagers age < 30 years, despite the high density of metacercariae in the crabs, indicating a change in the habit of eating raw food among the younger people.

Paragonimiasis in Nan Province, northern Thailand.

Two cases of paragonimiasis were identified within the hill-tribe population living on the Thai-Laotian border of Nan Province, northern Thailand, where information on Paragonimus was then still limited. The patients were in the habit of eating improperly cooked crabs and freshwater prawns. A survey for natural intermediate hosts to complete the life cycle was in progress at that time, and the detection of paragonimiasis cases indicated that there was persistence of paragonimiasis in the endemic area of Nan Province.

Familial Infestation of Paragonimus westermani with Peritonitis and Pleurisy / 대한소화기학회지

Human paragonimiasis was endemic in Korea until the 1960's, and nowadays, the prevalence is decreasing. However, it is still one of the important helminthic diseases. Though it is essentially a pulmonary disorder, it may involve brain, muscle, mesentery, genital tract, pleura, peritoneum, spinal cord, spleen, and liver. We experienced two cases of paragonimiasis in a family who had ingested raw crabs together for 7 months. A 57-year-old female patient was admitted due to abdominal pain, diarrhea and tenesmus for 6 months. And, her 35-year-old son complained of cough, chest discomfort and dyspnea. The definite diagnosis for paragonimiasis could be made by the detection of the egg and adult worm from stool, sputum and involved lesion. Neither an egg or worm was detected. However, they were diagnosed based on the food history, laboratory data including serum eosinophilia, ELISA for specific IgG, pleural and peritoneal fluid examination, radiological findings, and intradermal tests. They were treated with praziquantel and their symptoms improved rapidly over 2 days. Both patients were asympromatic at a follow-up visit 2 months later.

The food-borne trematode zoonoses of Vietnam.

During the past couple of decades, numerous surveys for the occurrence and distribution of food-borne trematodes in Vietnam have been carried out. However, the majority of the data obtained have not been published in international journals, and therefore, the seriousness of these trematode parasitic zoonoses in the country has not been fully appreciated. To correct this, over 40 Vietnamese language reports and local publications were translated and organized as a status review for an international audience. The results show that such serious trematode zoonoses as clonorchiasis, opisthorchiasis, paragonimiasis and fascioliasis are common in many regions of Vietnam, and, in the case of fascioliasis and paragonimiasis, are increasing. Data on the species of intermediate hosts involved in the transmission of these zoonoses, and the effect of host sex and age on infection frequencies are presented, along with findings on food preference/behavior investigations. Finally, the authors present recommendations for further research to provide a more comprehensive picture of the status of these zoonoses, and to obtain the risk assessment information needed to design prevention and control programs.

Epidemiology, symptoms and treatment of paragonimiasis in Sin Ho district, Lai Chau province, Vietnam.

Sin Ho is a district of the northern mountainous province of Lai Chau, Vietnam, where the people have the habit of eating undercooked crabs. A study on paragoniamiasis carried out from 1994 to 1995 with 1,642 persons in this endemic area, showed that the rate of eating raw-crab was 72.5%. Crab examination (Ranguna kimboiensis) showed an infection rate of Paragonimus metacercaria of 98.1%. With 624 stool samples examined by Kato technique, the infection rate of Paragonimus in humans was 6.4%. With 338 sputum samples examined by direct and centrifuge methods, the infection rate of Paragonimus was 7.4%. Most of the patients were children (63.2%). The infection rate of Paragonimus in dogs was 18.2 - 33.3%. Adult worms, collected from the dogs in the field and from the cats in laboratory, were identified as Paragonimus heterotremus. The main symptoms of Paragonimus patients were cough and hemoptysis (92%), discontinuously developed (96%), without fever (94%), chest pain (70%), pleural effusion (26%), neurogical symptoms (8%), eosinophilia (88.9%), nodular ring shadows in the lungs, as shown by chest X-ray examination and more in lower lobe, (76.2%). Paragonimiasis patients were treated by (a) Praziquantel 25 mg/kg/day x 3 days; the cure rate was 68.8%. (b) Praziquantel 50 mg/kg/day x 3 days; the cure rate was 75%.

Fish- and shellfish--borne trematode infections in Canada.

Food-borne trematode infections are endemic in various parts of the world, particularly Southeast Asia. Despite the high prevalence, morbidity and total costs of these infections, they remain poorly recognized by public health authorities and consumers. Factors such as poor sanitation and traditional methods of food preparation hasten the spread of food-borne trematode infections in endemic regions and must be carefully examined in order to develop effective control strategies. There is also a growing risk to consumers in non-endemic countries as a result of international trade. A considerable quantity of freshwater fish and shellfish is imported into Canada from endemic countries in Southeast Asia. Some of these products are imported fresh or processed in such a way that the infective metacercariae may not be destroyed. Further, current inspection procedures in Canada may not detect the presence of all parasites in imported fish products. Therefore, there may be a risk of infection if the fish or shellfish is consumed raw or lightly cooked. Many of the cases of infection in Canada involve recent immigrants from endemic regions who have become infected either before arriving or through the consumption of traditional or ethnic dishes prepared from imported products. International travel and the increasing availability and interest in ethnic foods also contribute to the risk of infection in all Canadians. In addition to these imported trematodes, a number of species are found in freshwater fishes and shellfish in North America and have also caused illness in humans. Although the prevalence of infection remains relatively low in Canada, the need for an increased general awareness of food-borne trematode infections and their causes is indicated.

Avaliaçäo do programa de controle da esquistossomose (pce/pcden) em municípios situados na Bacia do Rio Säo Francisco, Minas Gerais, Brasil / Evaluation of the control on schistosomiasis (PCE/PCDEN) in the municipalities of the region of Säo Francisco river, Minas Gerais, Brazil

An evaluation of the control program on schistosomiasis (PCE/PCDEN) was performed in the region of Säo Francisco river in MInas Gerais. The study area comprises six municipalities, with 130,000 inhabitants and 916 localities situated in an area with 10,722 km2. The activities initiated in 1983-85 in four municipalities and in 1987 in the other two. The main measures of control were repeated treatment with oxamniquine and use of niclosamide. The prevalence of infection by Schistosoma mansoni in the first four municipalities, that was initially around 18 and 32 per cent, dropped abruptly after the first intervention (1983/85) and remained in levels below the initial ones until the last assessment (1990-94); similar trends were observed for the proportion of infected snails. In these municipalities, the proportion of localities without infection or with prevalence below 5 per cent increased in relation to those with higher prevalence. In the other two municipalities, with initial prevalence below 5 per cent, there were no substantial changes in S. mansoni prevalence or proportion of infected snails; the cost benefit of the program in these municipalities need to be assessed and the priorities redirected to eradicate focal areas and prevent spread to non infected localities. The authors call attention to the difficulties in the long term of a control program based on repeated treatments. Information on factors associated with S. mansoni infection in each locality, or in groups of similar localities, would allow to develop additional measures to treatment that could last longer and be less dependent on the continuous use of chemotherapy.

Studies on clinical manifestations, diagnosis and control of paragonimiasis in China.

Paragonimiasis is a common parasitic zoonosis in China. Its clinical manifestations may be classified into two clinical entities, eg, paragonimiasis westermani type and paragonimiasis szechuanensis type. The latter mainly manifests as trematode larva migrans. The immunodiagnostic methods frequently used in the diagnosis of paragonimiasis are intradermal test, CFT and ELISA. The detection of circulating antigens in patients has been used in China for diagnosis and bithionol and praziquantel are drugs of choice in the treatment of paragonimiasis. Combined measures including mass survey, mass treatment and health education have been found to be effective in the control of paragonimiasis in China.

Paragonimiasis in Mae Hong Son Province northern Thailand: case report.

Two cases of paragonimiasis have been reported from Srisangval Hospital, Mae Hong Son Province, Thailand. These two patients (Thai-Karen) resided in Nam-Piang-Din, Mae Hong Son. The preliminary survey for epidemiological data in Nam-Piang-Din, Mae Hong Son revealed that most of Thai-Karen villagers had the habit of eating raw crabs and fresh water prawns. A survey for intermediate and reservoir hosts are still in progress and this area can be considered as an additional area for paragonimiasis in Thailand.

Epidemiology of marine fish-borne parasitic zoonoses.

Most parasites of marine animals are of little public health concern; however, some helminths are capable of infecting humans. Marine zoonotic infections in humans result from consumption of contaminated edible tissues or products of seafood or, to a lesser extent, from physical contact with contaminated seafood. Worldwide, over 50 species of helminth parasites from fishes, crabs, crayfishes, snails, and bivalves are known to produce human infections. Most helminth zoonoses are rare and invoke only slight to moderate injury; however, some are more prevalent and pose serious potential health hazards. Worldwide, the majority of seafood zoonoses occur along coastal regions where seafood products are commonly consumed. Continuing improvements in transportation, technology, and food handling, however, allow fresh seafood to be shipped throughout the world; thus, the potential for acquisition of parasitic infections from marine products is not limited to coastal populations. Although the number of documented cases continue to increase, the overall risk of human infection is slight. The increasing exploitation of the marine environment by humans, changing dietary habits incorporating "natural" seafood dishes (eg, sushi and sashimi), and tendency to reduce cooking times when preparing seafood products, all increase the chances of becoming infected with these parasites.