Below is a set of questions SCI was asked by a potential donor.  Professor Alan Fenwick answered the questions personally and has posted the questions and answers below for others to see.

We are very happy to entertain any questions from our donors and supporters so please email us on


How do people get infected?

Schistosomiasis: People are infected by schistosomiasis (schistosome worms) by coming into contact with contaminated fresh water in the tropics. Free living larvae are released by snails into the water and can penetrate a person’s skin. Once inside the body, the larvae migrate to the liver and develop into male and female worms that pair up and live together in the blood vessels for years. Female worms release hundreds of eggs every day, some of which are passed out of the body in the urine and faeces. If people urinate or defecate in bodies of freshwater, the eggs hatch and the emergent larvae migrate to snails which they infect, multiply inside the snail, and then begin the cycle again.

In areas without sanitation the cycle will continue because infected people contaminating the water can maintain the cycle of infection.

For soil-transmitted helminth there are several ways people are infected. For two worms, (Ascaris and Trichuris) infection happens when eggs are swallowed, usually with food. The adult worms in the intestine lay eggs which are passed out in the faeces. The eggs find their way onto food or people’s hands when people come into contact with the soil and do not adequately wash their hands. The third STH (hookworm) infects people actively by invading through the skin while walking barefoot through grass on which the hookworm larvae are lying in wait.

With improved sanitation, and hand washing, the cycle of infection could so easily be broken, and of course people wearing shoes will not get infected with hookworm. 

How often is treatment given and why?

Every country programme is tailored to meet their needs. The strategy may be different for countries based on how heavily infected an area is and the country’s treatment plan. According to the WHO guidelines any district that has over 50% of the population infected should consider delivering treatment twice a year while a country with 10-50% of the population infected is recommended to only treat once a year. In countries that have less than 10% infected they might only offer treatment every 3 years so that school aged children receive treatment at least twice before they leave school. For the identified high risk groups, such as fishermen, farmers and women of child bearing age who are heavily infected annual treatment might be recommended to reduce their contribution to transmission, but more importantly to reduce the morbidity they will suffer if not treated.  

Why do we need to treat again and again?

Currently there are no vaccines against schistosomiasis or STHs. There have been some clinical trials with candidate vaccines, but a commercial vaccine is surely a long way off.

We need to treat regularly for a number of reasons:

  • Praziquantel is effective only against mature worms. Therefore any immature worms inside the body will develop to maturity after the treatment.
  • People in the tropics will continue to be exposed to new infection, and there is little evidence that treated people are in any way resistant to a new reinfection.
  • Children playing, women washing clothes, fishermen and agricultural workers, all come in contact with contaminated water daily and are in danger of being reinfected.
  • We need to remember that treatment keeps the number of worms and the number of eggs laid to a minimum and therefore helps the people treated. We are currently protecting a generation of children from very serious consequences, and long may that continue.  

Which 5 drugs compose the "rapid impact package"?

The drugs used against NTDs are donated by the pharmaceutical industry. They are Albendazole (which is used for deworming and for lymphatic filariasis ((LF)), Mectizan (active against onchocerciasis and LF), Praziquantel (which treats schistosomiasis), Zithromax (the antibiotic active against trachoma) and Mebendazole (an alternative drug for deworming).

The drugs are not delivered all together, but can be delivered in pairs or even using triple therapy in some cases. As a general rule, SCI treats with albendazole and Praziquantel at the same time when targeting schistosomiasis and STH.  Typically the drugs are delivered as a single dose annually, although in heavy infection areas treatment twice a year may be more effective.  In areas of very low prevalence treatment every 3 years might be sufficient.

As for triple therapy, in some countries, such as Malawi, they are using three at once under certain circumstances. It depends on the focality of the diseases. We try to be flexible to get the best use out of donated drugs and limited resources. 

What are the known serious or severe adverse events associated with administration of drugs for NTDs?

Side effects from taking the 5 drugs are mostly rare and transient with no serious adverse effects. Some adverse effects have been reported after Praziquantel treatments, and people dislike the taste and have reported headaches and stomach aches after treatment. There have been no confirmed serious effects, and over 100 million people have been treated globally in the last few years alone. Mild abdominal pain, nausea, vomiting, diarrhoea and fatigue are the most frequently reported complaints and very few individuals require medical treatment. If children vomit (which does happen) the child is usually given a quiet place to rest. We try very hard not to treat any child who is sick or hasn’t eaten prior to treatment because this will increase the likelihood of a reaction. Children are encouraged to wait till they are feeling better and to eat first.  However there is one exception to this safety statement, although it does not involve praziquantel - if albendazole and Mectizan are given against Lymphatic Filariasis treatment to someone co-infected with Loa Loa serious reactions have been encountered and so in a Loa area treatment should be withheld.

Can you point me to a summary of how DALYs are estimated for the NTDs?

SCI staff regularly lecture at Imperial and at outside venues and so we have a set of lecture notes on various topics including DALYs (the number of years of healthy life lost attributable to a disease or group of diseases) and you can request a copy if you are interested. 

Are the drugs only given to the children?

Our main target is to reach children, because there is an immediate improvement to their health and they will be protected from future serious consequences. School attenders are easier to reach, but reaching out to non-school attenders is very important. Once we have reached the children, we would like to reach out to high risk groups in high endemic areas – (fishermen, farmers and women of child-bearing age). Our aim will be to reach all age groups that need treatment when praziquantel is in unlimited supply, and funding is available to deliver the extra drugs.

Is there any clinically significant drug resistance to these drugs?

Some tolerance has been reported to Praziquantel but no true resistance. Some Mectizan tolerance in Ghana has been reported but again only rarely. Our belief is that resistance to praziquantel is unlikely because of its unique mode of action. 

Who actually delivers the treatments?

NTD control programmes are MINISTRY OWNED. SCI assists Ministries of Health and the Ministries of Education in all cases to make their programmes successful - it is health staff and teachers who deliver the drugs not SCI staff.

We rely on country nationals to make the implementation more cost effective, to nurture country ownership of the programmes, and indeed sustainable capacity building. SCI personnel act as advisors in the process, bringing their expertise and experience where needed. 

Accordion 2

What monitoring and evaluation reports can we read on an annual basis to assess whether to keep donating to SCI?

In every country we carry out coverage surveys to ensure the treatments have been delivered. We select “sentinel sites” to assess the drug acceptability, and then conduct parasitology surveys and measure and heights and weights and haemaglobin follow ups on a cohort of children in each site. We publish our results in peer reviewed journals and post the references on the website. This list is updated regularly with the latest publications.

As a small donor, where exactly is my money going?

We have one or two large grants which are specifically awarded for certain countries. Donations from individuals are pooled and used where they will bring the most benefit.  Currently we use these pooled donations to help start new treatment programmes in countries which aren’t supported by larger grants. We have used pooled funding in Burundi, Cote D’Ivoire, DRC, Ethiopia, Malawi, Mauritania, Mozambique, Sudan, Zambia and Zanzibar.

What will money we give be spent on?

An estimated 90% of these donations go to the countries in Africa and are used to meet the costs for advocacy, transport, per diems, monitoring and evaluation etc. Imperial College kindly receives only a small overhead (6%) from charitable donations when they are "converted” to a project.

How are the drugs donated?

The drug companies donate their drugs as part of their corporate responsibility. GSK, Merck, Merck KGaA and J&J donate respectively Albendazole, Ivermectin and Praziquantel and Mebendazole. The drugs are not donated to SCI but through a WHO mechanism to the countries. Once the drugs are in the countries and in the Central Medical Stores, then SCI assists with transportation through to the end user.

Merck KGaA have incrementally increased their donation from 20 million tablets a year in 2008 to 250 million tablets a year in 2016 – enough to treat up to 100 million children.

Between the big pharma over 1 billion treatments are donated every year.

What finances do SCI receive from the drug companies?

SCI has not received any funding from the pharmaceutical industry.