Bilharzia in the Philippines: past, present, and future

Abstract

Schistosomiasis japonica has a long history in the Philippines. In 1975, 24 endemic provinces were identified in the northern, central, and southern islands of the Philippines. More than five million people were at risk, with approximately one million infected. In 2003, new foci of infection were found in two provinces in the north and central areas. For the past 30 years, human mass drug administration (MDA), utilizing the drug praziquantel, has been the mainstay of control in the country. Recent studies have shown that the schistosomiasis prevalence ranges from 1% to 50% within different endemic zones. Severe end-organ morbidity is still present in many endemic areas, particularly in remote villages with poor treatment coverage. Moreover, subtle morbidities such as growth retardation, malnutrition, anemia, and poor cognitive function in infected children persist. There is now strong evidence that large mammals (e.g. water buffaloes, cattle) contribute significantly to disease transmission, complicating control efforts. Given the zoonotic nature of schistosomiasis in the Philippines, it is evident that the incidence, prevalence, and morbidity of the disease will not be controlled by MDA alone. There is a need for innovative cost-effective strategies to control schistosomiasis in the long term.

Advances in the Diagnosis of Human Schistosomiasis

“…Schistosome-induced hepatic damage is due mainly to the formation of granulomas and fibrosis around the schistosome eggs lodged in presinusoidal portal venules, and these immunologically based outcomes are responsible for most of the serious sequelae associated with chronic schistosomiasis (16,285). This pathological process results in structural and biochemical changes in the liver.…”

Evaluation of banked urine samples for the detection of circulating anodic and cathodic antigens in Schistosoma mekongi and S. japonicum infections: A proof-of-concept study

“…In Asia, Schistosoma japonicum is found in the People's Republic of China (P.R. China), the Philippines (Olveda et al, 2014;Zhou et al, 2010) and Indonesia (Satrija et al, 2015), while the infection is caused by Schistosoma mekongi in Cambodia and Lao People's Democratic Republic (Lao PDR) (Muth et al, 2010).…”

Emerging Infectious Diseases in Water Buffalo: An Economic and Public Health Concern

“…and effective integrated treatment and control for infected host and intermediate host, respectively. The use of predators (ducks and frogs) and molluscicides for control and possible elimination of the snail intermediate host is impossible as it is labor extensive, costly and may disturb the ecological balance in the area [297]. Vaccine development was vigorously pursued, however, despite persistent efforts, a vaccine with adequate protection against fasciolosis has not yet been developed to the point of commercialization [297].…”

“…In cases of cryptosporidiosis, high prevalence of the disease is due to contamination of oocyst in the environment from great oocyst shedding in feces and survival of oocyst for few weeks to months [227,228]. Schistosomiasis and fasciolosis are difficult to control due to non-conformity to habitual good and proper husbandry practices, continuous transmission from shedder animals, quantity of intermediate and final host, malpractices of irrigation systems and poor hygiene management [245,297,299].…”