Effects of schistosomes on host anti-viral immune response and the acquisition, virulence, and prevention of viral infections: A systematic review

Abstract

Although a growing number of studies suggest interactions between Schistosoma parasites and viral infections, the effects of schistosome infections on the host response to viruses have not been evaluated comprehensively. In this systematic review, we investigated how schistosomes impact incidence, virulence, and prevention of viral infections in humans and animals. We also evaluated immune effects of schistosomes in those coinfected with viruses. We screened 4,730 studies and included 103. Schistosomes may increase susceptibility to some viruses, including HIV and Kaposi’s sarcoma-associated herpesvirus, and virulence of hepatitis B and C viruses. In contrast, schistosome infection may be protective in chronic HIV, Human T-cell Lymphotropic Virus-Type 1, and respiratory viruses, though further research is needed. Schistosome infections were consistently reported to impair immune responses to hepatitis B and possibly measles vaccines. Understanding the interplay between schistosomes and viruses has ramifications for anti-viral vaccination strategies and global control of viral infections.

Diarrhoea‐causing enteric protist species in intensively and extensively raised pigs ( Sus scrofa domesticus ) in Southern Spain. Part II: Association with Hepatitis E virus susceptibility

“…Thus, immune-mediated process has been also described in extra-intestinal infections by trematode parasites such as Schistosoma spp. (Bullington et al, 2021). This helminth infection is associated with a worst prognosis in those individuals co-infected with human immunodeficiency virus or hepatitis C virus, a higher reactivation rate among Herpesvirus-infected patients, or a lower likelihood to reach immunity after vaccination against measles and hepatitis B virus (Bullington et al, 2021).…”

“…This helminth infection is associated with a worst prognosis in those individuals co-infected with human immunodeficiency virus or hepatitis C virus, a higher reactivation rate among Herpesvirus-infected patients, or a lower likelihood to reach immunity after vaccination against measles and hepatitis B virus (Bullington et al, 2021). This effect is also related with impairment of the immune system (Bullington et al, 2021), characterized by a decrease in Th1 response. In contrast, this effect is associated with a subsequent increase on Th2 responses, which response (increased levels of IFN-γ, IL-1β, IL-6 and TNF-α) followed by a predominant Th2 response (Serradell et al, 2018).…”

“…This helminth infection is associated with a worst prognosis in those individuals co‐infected with human immunodeficiency virus or hepatitis C virus, a higher reactivation rate among Herpesvirus‐infected patients, or a lower likelihood to reach immunity after vaccination against measles and hepatitis B virus (Bullington et al., 2021). This effect is also related with impairment of the immune system (Bullington et al., 2021), characterized by a decrease in Th1 response. In contrast, this effect is associated with a subsequent increase on Th2 responses, which leads to a better immune control.…”

“…In contrast, this effect is associated with a subsequent increase on Th2 responses, which leads to a better immune control. In this sense, patients with influenza infection showed a lower rate of mortality and morbidity when co‐infected with Schistosoma parasites (Bullington et al., 2021). In the case of extracellular enteroparasites, such as G. duodenalis or Blastocystis sp., we have previously discussed the possible indirect effect of an immune‐mediated mechanism in protecting the host against HEV infection (Rivero‐Juarez et al., 2020).…”

Schistosoma mansoni Infection Is Associated With Increased Monocytes and Fewer Natural Killer T Cells in the Female Genital Tract

“…How S. mansoni alters the cervical immune compartment and mechanisms by which S. mansoni could impair genital mucosal antiviral immunity have been minimally investigated. Understanding this interaction could provide insight into immune effects of S. mansoni in the genital tract and help explain disparities in viral infections in women in countries where schistosomiasis is endemic [ 13 ].…”