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Caracterização genética de Cryptosporidium spp. em amostras biológicas de humanos e animais provenientes da Roménia: comparação com as características dos organismos obtidos das populações humana e animal portuguesa
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As espécies de Cryptosporidium são parasitas apicomplexa ubíquos e importantes agentes etiológicos de doença gastrintestinal. A infecção por Cryptospordium spp. pode ser adquirida por diversas vias de transmissão, sendo a diarreia o sinal mais frequente de doença. Uma grande variedade de animais e os humanos são infectados, sendo os imunocomprometidos e os jovens os grupos mais susceptíveis à infecção. Os humanos são infectados principalmente por duas espécies, Cryptosporidium hominis (transmissão antroponótica) e Cryptosporidium parvum (transmissão antroponótica ou zoonótica), enquanto o gado doméstico pode ser infectado por várias espécies de Cryptosporidium. Nos últimos anos, as ferramentas moleculares têm permitido aprofundar o conhecimento acerca da epidemiologia destes parasitas. O elevado polimorfismo apresentado por alguns loci têm permitido caracterizar a diversidade genética ao nível do subtipo, conduzindo a uma melhor compreensão das fontes de infecção e dinâmicas de transmissão em humanos e animais. Com este trabalho pretendemos caracterizar geneticamente as espécies de Cryptosporidium de origem humana e animal provenientes da Roménia através da técnica de nested-PCR aplicada a dois loci, a subunidade pequena do ácido ribonucleico ribossómico e a glicoproteína de 60-kDa, com a finalidade de compreender os principais reservatórios presentes neste país. No presente estudo, a frequência geral de infecção em crianças foi 36,4% (4/11), em vitelos foi 62,1% (18/29), e em porcos 25% (2/8). A análise das sequências revelou que todos os isolados são Cryptosporidium parvum. Duas famílias de subtipo foram identificadas, IIa e IId. O subtipo IIdA22G1 de C. parvum foi o único caracterizado nas crianças (n=4). Em vitelos foram identificados os subtipos IIdA27G1 (n=8), IIdA25G1 (n=5), IIdA22G1 (n=2), IIdA21G1a (n=1) e IIaA16G1R1 (n=1), enquanto nos suínos apenas foi identificado o subtipo IIdA26G1 (n=1). Estes resultados mostram uma perspectiva epidemiológica muito diferente dos estudos romenos anteriores, uma vez que os cinco subtipos da família IId identificados neste estudo nunca foram identificados anteriormente no país, mostrando que a dinâmica de transmissão na Roménia é mais complexa do que as conclusões anteriores. Por sua vez, em Portugal parece existir uma maior diversidade genética de isolados de Cryptosporidium spp. Até à data foram identificadas quatro famílias de subtipo de C. parvum, IIa, IIb, IIc e IId, verificando-se que o subtipo IIaA15G2R1 foi o mais frequente em ambas as populações. Além deste foram identificados quatro subtipos na família IId, dois dos quais são comuns ao nosso estudo, nomeadamente IIdA21G1 e IIdA22G1. A comparação entre os nossos resultados e aqueles encontrados em Portugal revela que apesar de existirem algumas diferenças relativamente à dinâmica de transmissão na população humana de Portugal e do distrito de Timis da Roménia, no geral, os reservatórios e os modos de transmissão em ambos os países são bastante semelhantes.
Cryptosporidium species are ubiquitous apicomplexan parasites and important etiological agents of gastrointestinal disease. Cryptosporidium infection has several transmission routes, being diarrhea the most frequent sign of disease. A wide range of animals and humans are infected, being immunocompromised individuals and the youngsters the groups more susceptible to infection. Humans are mainly infected by two species, Cryptosporidium hominis (anthroponotic transmission) and Cryptosporidium parvum (zoonotic or anthroponotic transmission), whereas cattle can be infected by several species of Cryptosporidium. In recent years, molecular tools have improved the knowledge about the epidemiology of these parasites. Some loci have revealed high degree of polymorphisms allowing characterize genetic diversity at subtype level, leading to a better understanding of sources of infection and transmission dynamics in humans and animals. With this work we intend to genetically characterize Cryptosporidium spp. organisms of human and animal origin, from Romania, using nested-PCR techniques applied to two loci, small subunit ribosomal ribonucleic acid and 60-kDa glycoprotein, with the purpose to understand the main reservoirs present in this country. In the present study, the overall frequence of infection in children was 36.4% (4/11), in calves was 62.1% (18/29), and in pigs was 25% (2/8). Sequence analyses revealed that all isolates were Cryptosporidium parvum. Two subtype families were identified, IIa and IId. Subtype IIdA22G1 (n=4) was the single C. parvum subtype characterized in children. The subtypes identified in calves were IIdA27G1 (n=8), IIdA25G1 (n=5), IIdA22G1 (n=2), IIdA21G1a (n=1) and IIaA16G1R1 (n=1), and in pigs, the IIdA26G1 subtype (n=1) was the only one observed. These results show a remarkable different epidemiologic perspective from previous romanian reports, since the five subtypes of family IId identified in this study have never been identified previously in this country, showing that transmission dynamics in Romania is more complex than previous conclusions. Meanwhile, in Portugal there seems to be a greater genetic diversity of Cryptosporidium spp. in both animal and human populations. To date four C. parvum subtype families were identified, IIa, IIb, IIc and IId, verifying that IIaA15G2R1 subtype was the most frequent in humans and bovine populations. In addition to this, four subtypes have been identified in the IId subtype family, two of which are common to our study, including IIdA21G1 and IIdA22G1. The comparison of our results obtained with the Romanian populations studied and those found in Portugal show that although there are some differences regarding the transmission dynamics of the human populations of Portugal and the Timis county of Romania, in general, the reservoirs and modes of transmission in both countries are very similar.
Cryptosporidium species are ubiquitous apicomplexan parasites and important etiological agents of gastrointestinal disease. Cryptosporidium infection has several transmission routes, being diarrhea the most frequent sign of disease. A wide range of animals and humans are infected, being immunocompromised individuals and the youngsters the groups more susceptible to infection. Humans are mainly infected by two species, Cryptosporidium hominis (anthroponotic transmission) and Cryptosporidium parvum (zoonotic or anthroponotic transmission), whereas cattle can be infected by several species of Cryptosporidium. In recent years, molecular tools have improved the knowledge about the epidemiology of these parasites. Some loci have revealed high degree of polymorphisms allowing characterize genetic diversity at subtype level, leading to a better understanding of sources of infection and transmission dynamics in humans and animals. With this work we intend to genetically characterize Cryptosporidium spp. organisms of human and animal origin, from Romania, using nested-PCR techniques applied to two loci, small subunit ribosomal ribonucleic acid and 60-kDa glycoprotein, with the purpose to understand the main reservoirs present in this country. In the present study, the overall frequence of infection in children was 36.4% (4/11), in calves was 62.1% (18/29), and in pigs was 25% (2/8). Sequence analyses revealed that all isolates were Cryptosporidium parvum. Two subtype families were identified, IIa and IId. Subtype IIdA22G1 (n=4) was the single C. parvum subtype characterized in children. The subtypes identified in calves were IIdA27G1 (n=8), IIdA25G1 (n=5), IIdA22G1 (n=2), IIdA21G1a (n=1) and IIaA16G1R1 (n=1), and in pigs, the IIdA26G1 subtype (n=1) was the only one observed. These results show a remarkable different epidemiologic perspective from previous romanian reports, since the five subtypes of family IId identified in this study have never been identified previously in this country, showing that transmission dynamics in Romania is more complex than previous conclusions. Meanwhile, in Portugal there seems to be a greater genetic diversity of Cryptosporidium spp. in both animal and human populations. To date four C. parvum subtype families were identified, IIa, IIb, IIc and IId, verifying that IIaA15G2R1 subtype was the most frequent in humans and bovine populations. In addition to this, four subtypes have been identified in the IId subtype family, two of which are common to our study, including IIdA21G1 and IIdA22G1. The comparison of our results obtained with the Romanian populations studied and those found in Portugal show that although there are some differences regarding the transmission dynamics of the human populations of Portugal and the Timis county of Romania, in general, the reservoirs and modes of transmission in both countries are very similar.
Descrição
Palavras-chave
Microbiologia médica Biologia molecular Epidemiologia médica Cryptosporidium parvum Crianças Vitelos GP60 Subtipos
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical