Hypolobocera guayaquilensis (Decapoda: Pseudothelphusidae): A New Crab Intermediate Host of Paragonimus mexicanus in Manabí Province, Ecuador.

To determine that Paragonimus sp. is actively transmitted in a tropical area of the Pacific region of Ecuador where human cases of pulmonary paragonimiasis have recently been documented, a total of 75 freshwater crabs were collected from 2 different streams in the Pedernales area of Manabí Province, Ecuador. All collected crabs were identified as Hypolobocera guayaquilensis based on morphological characteristics of the male gonopods. The hepatopancreas of each crab was examined by compressing it between 2 glass plates followed by observation under a stereomicroscope. Excysted Paragonimus metacercariae were detected in 39 (52.0%) crabs and their densities varied from 1 to 32 per infected crab. There was a positive relationship between crab size and metacercarial density. Sequences of the second internal transcribed spacer region of the ribosomal RNA gene of the Paragonimus metacercariae obtained in this study were identical to those of Paragonimus mexicanus deposited in the DDBJ/EMBL/GenBank database. Thus, the present study is the first to confirm that the crab species H. guayaquilensis is the second intermediate host of P. mexicanus in Manabí Province, Ecuador. Because this crab might be the possible source of human infections in this area, residents should pay attention to improper crab-eating habits related with a neglected parasitic disease, i.e., paragonimiasis.

Inactivation of Paragonimus westermani metacercariae in soy sauce-marinated and frozen freshwater crabs.

Soy sauce-marinated freshwater crabs (Eriocheir japonicus) are a source of human paragonimiasis. The viability of Paragonimus westermani metacercariae (PwMc) in marinated crabs was investigated in an experimental setting. The PwMc collected from freshwater crayfish were inoculated into freshwater crabs, which were then frozen or marinated in soy sauce. All PwMc in the freshwater crabs were inactivated after freezing for 48 h at -20 °C and after freezing for 12 h at -40 °C. After marinating for 32 days, the survival rate of PwMc in 5% NaCl soy sauce was 50%, in 7.5% NaCl soy sauce it was 33.3%, and in 10.0% NaCl soy sauce it was 31.3%. When marinated for 64 days, all PwMc were inactivated in all experimental groups. These results revealed that freezing and soy sauce marination were detrimental to the survival of PwMc in freshwater crabs. Specifically, freezing crabs for more than 48 h or soaking them in soy sauce containing at least 5.0% NaCl for 64 days can inactivate PwMc. These results can inform the production of the traditional Korean soy sauce-marinated freshwater crabs known as gejang.

Integrated surveillance of pulmonary tuberculosis and paragonimiasis in Zamboanga del Norte, the Philippines.

BACKGROUND: Pulmonary tuberculosis (PTB) and paragonimiasis remain as health problems in certain areas in the Philippines. Both share similar clinical manifestations, which include chronic productive cough, hemoptysis, dyspnea, fever, weight loss, and night sweats. This study aimed to determine the prevalence of PTB, paragonimiasis, and co-infections in Zamboanga del Norte, Philippines. METHODS: This study was conducted in selected villages in two municipalities in Zamboanga del Norte. Patients with chronic cough were interviewed, examined, and requested to submit two sputum samples which were processed using Ziehl-Neelsen method to detect acid-fast bacilli (AFB), and NaOH concentration technique for the detection of Paragonimus ova. RESULTS: A total of 836 patients submitted sputum samples for examination. Prevalence was 6·7% (2·5-12·7%) for paragonimiasis and 1·9% (0·9-6·3%) for PTB. Co-infection rate was 0·3%, with two identified cases. Positivity rates for males and females were 9·6 and 5·8% for paragonimiasis and 3·4 and 1·2% for PTB. CONCLUSION: Pulmonary tuberculosis and paragonimiasis are co-endemic in Zamboanga del Norte, suggesting the need to integrate surveillance and control efforts. Strengthening local health systems through collaboration between different sectors is recommended for effective disease control. Development of more sensitive diagnostic tests is important for more accurate disease surveillance.

[Paragonimus sp. in crabs and awareness of the educational community to aquatic ecosystems in La Miel and La Clara, Caldas, Antioquia]. / Paragonimus sp. en cangrejos y sensibilización de la comunidad educativa hacia los ecosistemas acuáticos de La Miel y La Clara, Caldas, Antioquia.

INTRODUCTION: Previous research has demonstrated the presence of Paragonimus spp. in crabs of three municipalities located in the Medellín river basin. To design a plan for the control and prevention of paragonimosis, parasite presence must be demonstrated in the upper area of the river, and an awareness campaign of its risks must involve the participation of the educational community in focusing attention on the local aquatic resources. OBJECTIVE: The presence of Paragonimus spp. metarcercariae was established in freshwater crabs from La Miel and La Clara streams, and an awareness campaign created public awareness to management of the aquatic ecosystems for risk reduction. MATERIALS AND METHODS: Nine crabs were collected from streams of La Miel and La Clara villages in 2007 and 2008. The crabs were indentified, sacrificed in the laboratory and examined for presence of Paragonimus spp. metacercariae. Five workshops were conducted with students of educational institutions of the two villages to improve the student perception of paragonimosis risks associated with the local streams. RESULTS: The crabs were identified as Hypolobocera bouvieri. One crab was found with Paragonimus spp. in La Miel. A mollusk, Aroapyrgus colombiensis, another host of the parasite was found in La Clara. That aquatic ecosystems are a great attraction for the local was well established. CONCLUSIONS: Foci of Paragonimus spp. flatworms are present in the upper area of Medellín river which includes Caldas. However, local school children were uninformed about the risk of paragonimosis associated with the local aquatic ecosystem. Therefore this province must be included in programs for prevention and control of paragonimosis. The prevalence of this disease recommends educational programs that promote awareness of local aquatic ecosystems and their parasitic inhabitants.

Estudio de foco de paragonimosis en Fuente Clara, Robledo, área periurbana de Medellín, Antioquia / Paragonimosis in the peri-urban zone of Medellín, Antioquia

Introducción. La información sobre paragonimosis humana en Colombia llevó a suponer que los focos de la enfermedad estaban localizados en sectores selváticos; sin embargo, durante 2005 se hallaron cangrejos infectados con Paragonimus sp. en Fuente Clara, zona urbana de Medellín. Esto motivó la investigación. Objetivo. Realizar un estudio ecoepidemiológico de la paragonimosis con la participación de la comunidad para promover un manejo adecuado de los ecosistemas acuáticos. Materiales y métodos. Se realizó búsqueda de huéspedes silvestres y humanos de Paragonimus sp. en Fuente Clara. La presencia de formas larvarias y gusanos adultos del digéneo se evaluó en moluscos, crustáceos y mamíferos. En las personas voluntarias se hizo diagnóstico en esputo. Al agua de la quebrada La Puerta se le midieron: coliformes totales/fecales, pH, conductividad y oxígeno disuelto. Con niños y adolescentes se realizaron talleres educativos utilizando técnicas lúdicas. Resultados. Los porcentajes de infección encontrados fueron: caracoles, 0,07 por ciento; cangrejos, 55,5 por ciento; mamíferos, 25 por ciento, y personas, 0 por ciento. Durante los talleres educativos se manifestó la importancia de los recursos naturales del barrio. Los niños identificaron los huéspedes de Paragonimus sp. y detectaron los factores de riesgo para adquirir la enfermedad. Se determinó que el agua de la quebrada La Puerta no es apta para el consumo y la recreación de las personas. Conclusiones. Se señala a Fuente Clara como el primer foco de paragonimosis en zona urbana de Colombia, donde la manipulación y el consumo de cangrejos ponen en riesgo de adquirir la infección a sus habitantes; se sugiere realizar vigilancia de la enfermedad en el sector.

Paragonimiasis: an important food-borne zoonosis in China.

The lung fluke, Paragonimus westermani, is of major socioeconomic importance in Asia. The parasite is transmitted via snails to freshwater crabs or crayfish, then to humans and other mammals, such as cats and dogs, and causes paragonimiasis. This review provides a background on the parasite and its life cycle; summarizes key aspects regarding the pathogenesis, diagnosis and treatment of paragonimiasis; describes the geographic distribution and prevalence of paragonimiasis; and makes some recommendations for future research and the control of this important disease in China.

Paragonimus westermani: biochemical and immunological characterizations of paramyosin.

Paramyosin of the helminth parasite is a muscle protein that plays multifunctional roles in host-parasite relationships. In this study, we have cloned a gene encoding Paragonimus westermani paramyosin (PwPmy) and characterized biochemical and immunological properties of the recombinant protein. The recombinant PwPmy (rPwPmy) was shown to bind both human immunoglobulin G (IgG) and collagen. The protein was constitutively expressed in various developmental stages of the parasite and its expression level increased progressively as the parasite matured. Immunohistological analysis revealed that PwPmy was mainly localized in subtegumental muscle, tegument and cells surrounding the oral sucker, intestine, and ovary of the parasite. Sera from patients with paragonimiasis showed antibody reactivity against rPwPmy, and IgG1 and IgG4 were predominant. Immunization of mice with rPwPmy also induced high IgG responses. Biochemical and immunological characterization of PwPmy may provide valuable information for the further study to develop a vaccine or a chemotherapeutic agent for paragonimiasis.

História natural da infecção por Paragonimus: abordagem clínica e ecológica / Natural history of Paragonimus’ infection: clinical and ecological approach

A paragonimíase é uma doença zoonótica, não-contagiosa, produzida por trematódeos do gênero Paragonimus. O homem e outros animais infectam-se ao ingerir crustáceos de água doce — crus, mal cozidos ou em conserva — ou, ainda, água e/ou alimentos contaminados com metacercárias. Apresenta evolução crônica e acometimento predominantemente pulmonar, ainda que sejam descritas descritas alterações extrapulmonares. Podem surgir sinais e sintomas como tosse com expectoração sanguinolenta, febre intermitente, dor torácica, suores noturnos e, mais raramente, astenia, anorexia e perda de peso. Como principais métodos diagnósticos destacam-se o exame a fresco do escarro e/ou das fezes do paciente e os testes imunológicos. O tratamento é realizado com praziquantel. A infecção, habitualmente, tem bom prognóstico.

Paragonimiasis and the genus Paragonimus.

The review concentrates on literature that has appeared since the 1960s. Since then, numerous species of Paragonimus have been described, mainly from Asia but also from Africa and the Americas. Some of these cause disease in humans. Recent information on life cycles and routes of transmission is summarized. All described species and their hosts are listed, with synonyms where known. For well-known species such as Paragonimus westermani, subspecific taxa and strains are reviewed and genetic studies discussed. Paragonimiasis in humans and experimental animals is discussed with emphasis on clinical manifestations and pathology, diagnosis, immune interactions with the host, treatment and public health issues.

Epidemiology of paragonimiasis in Korea.

In Korea, soybean-sauce soaked freshwater crabs (kejang) have been a favorite delicacy when eating a bowl of rice. This traditional food has been a main source of human paragonimiasis. Until the late 1960s, human paragonimiasis had been prevalent; at least two million people had contracted the infection as determined by intradermal tests. About 40% of these were egg positive. In the turmoil of the green revolution and industrialization in the 1970s/1980s, ecological damage occurred widely. In many streams, populations of snail and crustacean hosts were reduced to levels almost of extinction. Population reduction of the intermediate hosts was followed by lowered endemicity. Attitudes of people, changed during the period, also reduced chances of paragonimiasis. Survey data in the 1990s indicated that prevalence of human paragonimiasis has lowered to about one 100th of that in the early 1970s. In a referral system, however, about one hundred clinical cases have been diagnosed annually by antibody test (ELISA), undertaken for clinical differentiation from tuberculosis. At least 10% of freshwater crabs sold in local markets are infected with the metacercariae. Paragonimiasis control has benefited in Korea mainly by the untoward effects of water pollution. To place P. westermani infections as enzootic, health education and surveillance systems should have a priority.

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.

Endemic human paragonimiasis in Equatorial Guinea. Detection of the existence of endemic human paragonimiasis in Equatorial Guinea as a result of an integrated sanitary programme.

Between February and April 1990 the first five cases of human paragonimiasis, tentatively due to Paragonimus africanus, have been detected in Equatorial Guinea, thanks to the normal activities of the National Schistosomiasis Project and its coordination with the National Tuberculosis Project.

[Pulmonary paragonimiasis in Cameroun (author's transl)]. / La paragonimose pulmonaire au Cameroun.

The clinical and epidemiological features of pulmonary paragonimiasis are first described. Then, a brief and localized survey is reported in which 19 cases were detected. The disease has probably a higher prevalence than generally estimated. Eating raw or insufficiently cooked crab meat is the main cause of infection. Treatment is easy and so should be the prophylaxis.