Impact of the Three Gorges Dam on transmission and future control of human schistosomiasis in China

Multi-factorial randomised trial of integrated control on schistosomiasis incidence

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

ANZCTR

Registry ID

ACTRN12611000193976

Enrollment

6000

Registered

2011-02-18

Start date

2010-12-01

Completion date

Unknown

Last updated

2020-01-13

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

None listed

Brief summary

Our central thesis is that: When the TGD becomes fully operational in 2009, a wide variety of environmental and ecological changes will result downstream, impacting directly on the density and reproduction of the oncomelanid snail hosts for Schistosoma japonicum. The period that follows is critical as this will be the only time that the immediate effects of the TGD on schistosome transmission can be determined. It is predicted that The Dam will influence the transmission dynamics of human schistosomiasis, resulting in a substantially increased disease burden in communities along the Yangtze River, which will require an integrated control strategy to reduce the rate of transmission of S. japonicum from bovines and humans to snails. With this background, we will test the following specific hypotheses: 1. When fully operational in 2009, the TGD will result in reduced flooding in the downstream endemic areas extending the transmission season and expanding marshland areas, which will provide opportunities for the reproduction, dispersal and increased density of infected Oncomelania snails and hyper-endemic S. japonicum transmission. 2. The changing transmission dynamics will require improved cost-effective methods of surveillance and integrated schistosomiasis control. We will quantify the impact of integrated strategies for schistosomiasis control using a multi-factorial randomised design. The strategies we will employ are: 1.Combined human mass chemotherapy and bovine vaccination; 2.Combined bovine vaccination with mollusciciding of snails.

Interventions

Annual human praziquantel (single dose 40mg/kg oral tablet) Annual bovine praziquantel (single dose 25mg/kg oral tablet), Molluscicide: Niclosamide (2 g/m2) spray annually, Bovine vaccine SjCTPI-Hsp70/IL-12 DNA vaccine (single dose 500ug IM injection) (1 primary + 1 boost year 1; annual boost years 2-4) Intervention Vaccinated Bovines Placebo Bovines Mollusciciding 2 villages 2 villages Human PZQ 2 villages 2 villages Neither 2 villages

Study design

Allocation

Randomised controlled trial

Intervention model

Factorial

Primary purpose

Prevention

Masking

Blinded (masking used)

Eligibility

Sex/Gender

All

Age

5 Years to 65 Years

Healthy volunteers

Yes

Inclusion criteria

1. Resident of the administrative village and/or natural village selected for study. 2. Has been a resident of the village for >12 months. 3. 5-65 years of age. 4. Will not be migrating in the next 4 years. 5. Those who continuously reside in the study area over the study period. 6. The resident has given informed consent. 7. Minors have the informed consent of their parent/guardian.

Exclusion criteria

1. No consent 2. Resides less than 6 months of the year in the village

Outcome results