Schistosome infection and its effect on pulmonary circulation

Abstract

Schistosomiasis is the most common parasitic disease associated with pulmonary hypertension. It induces remodelling via complex inflammatory processes, which eventually produce the clinical manifestation of pulmonary hypertension. The pulmonary hypertension shows clinical signs and symptoms that are not distinguishable from other forms of pulmonary arterial hypertension.

Pulmonary hypertension: From an orphan disease to a global epidemic

“…There are different species of schistosomiasis, the most common to affect humans are S. mansoni , S. haematobium, and S. Japonicum . Chronic schistosomiasis is the most prevalent form of the disease in regions endemic for schistosomiasis, due to repeated exposure and re-infection 115,116 . The cardinal pathological component of the of schistosomiasis is not the mature worm, which has evolved immune evasion mechanisms that allow them to remain incognito within the bloodstream, but by the highly antigenic egg-associated pathology that is central to the morbidity and mortality 115 .…”

“…Chronic schistosomiasis is the most prevalent form of the disease in regions endemic for schistosomiasis, due to repeated exposure and re-infection 115,116 . The cardinal pathological component of the of schistosomiasis is not the mature worm, which has evolved immune evasion mechanisms that allow them to remain incognito within the bloodstream, but by the highly antigenic egg-associated pathology that is central to the morbidity and mortality 115 . Liver disease develops secondary to entrapment of eggs in portal venules and is initially presinusoidal, resulting in periportal fibrosis, and the development of “Symmers pipe stem fibrosis” 115,117 .…”

“…The highly antigenic eggs develop an immunological reaction that leads to the development of granuloma, and subsequent remodeling of pulmonary arterioles. Severe intimal, medial, and adventitial hypertrophy and a proliferation of inflammatory cells occurs in the pulmonary vasculature, which contributes to the development of pulmonary hypertension 115,119–122 .…”

“…The most recently available data of pulmonary hypertension patients have come from Brazil, which has a good schistosomiasis control program, and its clinical care is far superior to many developing countries. Their data estimated that 7.7% to 10.7% of patients may have some form of pulmonary hypertension secondary to schistosomiasis 115,124,125 ; but these estimates were based on case control studies rather a proper epidemiological evaluation.…”

Diagnóstico da infecção de Biomphalaria glabrata por Schistosoma mansoni em área de baixa endemicidade no Estado de São Paulo, utilizando técnicas de biologia molecular

“…mansoni (BH) em caramujos retirados de Ourinhos, que foi constatada pela Mesocricetus auratus) demonstrada pela positividade da técnica de Kato-Katz (Bio-manguinhos, Fiocruz 2014) (120 ovos por grama de fezes após 43 dias de infecção) desses animais associado aos achados anatomopatológicos compatíveis com a infecção pelo S. mansoni nos órgãos dos hamsters eutanasiados.Não foram encontrados ovos nas fezes do grupo de animais infectados com cercárias proveniente dos caramujos controle positivo do ciclo. Entretanto, percebeuse, analisando estudos anteriores, que a oviposição no ciclo rotineiro estabelecido em laboratório com caramujos BH pode ocorrer mais tardiamente(Espírito-Santo et al, 2014).Ainda, para completar a evidência de perpetuação do ciclo, a análise histopatológica deste estudo seguiu a mesma metodologia do trabalho desenvolvido porEspírito-Santo et al (2014).Foram observadas alterações anatomopatológicas em ambos os grupos de animais estudados, como a presença de hepatoesplenomegalia na análise macroscópica, e infiltrados inflamatórios em torno de ovos e vermes adultos na análise microscópica, bem como, granulomas esquistossomóticos no fígado, pulmão e intestino, além da congestão esplênica.Esses achados culminaram nos processos de fibrose periportal e pneumonite esquistossomótica, confirmando a morbidade da infecção experimental de hamsters, pelas cercárias liberadas do hospedeiro intermediário da linhagem Ourinhos(Butrous, 2019; Espírito-Santo et al, 2015). Assim sendo, esse trabalho, formou um novo ciclo experimental, com uma reprodução considerável e apontou um avanço na observação do comportamento da relação parasito-hospedeiro da esquistossomose.…”