Dear Mostafa

Yes globally I think there is a reduction of this disease

Many thanks to the efforts of scientists and the improvement in the knowledge, communications etc

I think many factors behind this reductions, as I said the improvement in the tools of

" Roll Back" in many fronts e.g water sanitation, hygiene and the safe single dose drug (Praziguantel)

Anyway the disease still has high prevalence in many part of the work with many morbidity and mortality and we have to sustain the effort and not to relax

warm Reagrds

Prof. Ishag Adam

Look also to Morocco, Brazil, Tunisia, Iran, Puerto Rico, St. Lucia, for places where schistosomiasis prevalence has dropped considerably or disappeared. In some cases, the change was due to sanitation improvements and to changes in water use, in some others it was the results of focused anti-parasite campaigns.

It is important to be cautious about these successes, because in many other countries, human population growth and migration, combined with creation of new snail habitat (mostly though dams and irrigation schemes) has significantly increased schistosomiasis prevalence. It is estimated that there are still > 237 million people infected today, mostly in sub-Saharan Africa.

Thank you Ishag. I agree with your however, following praziquantel, the morbidity of schistosomiasis varied. We no longer diagnose colonic polyps, pulmonary aneurythm and pure bilharzial liver fibrosis as we previously did. In our country, there is a change in the rank of cancer bladder associated with S. haematobium which was usually squamous cell carcinoma. Some colleagues contribute the decrease in schistosomal transmission to pollution of canal water and its probable effect on snails. However, this hypothesis needs study.

Dear Mostafa

In Latin America is well-known the significant decrease in the prevalence of Schisto in our region, particularly in countries such as Brazil and Venezuela. At the last Latin American Congress of Parasitology (Oct. 2013, Ecuador), Dr. Katz, the leader of those research in Brazil, presented impressive epidemiological data about those reductions. Until I now, they are about to publish some of that in this year.

Best regards,

Prof. Alfonso J. Rodriguez-Morales

Pereira, Colombia.

That's one half of the issue. I know that soil transmitted helminths are highly prevalent in certain Latin American countries. Is STH an issue for Egypt? Sanitation helps with both but treatment is different (albendazole/mebendazole)

Yes. Prevalence of shistosomiasis in iran is decreasing because of good snails controlling programs are done in iran.

Surveys on bilharziasis in Iran were established in 1949 and extended on wards. Accordingly it was confirmed that urinary bilharziasis exists in the province of Khuzestan in south-west of Iran. The number of people infected was timidly estimated as 25,000 - 35,000. The peak prevalence rate was reported in children aged 11-15 year and eventually Bulinus truncatus was determined as the only intermediate host. Reducing overall prevalence of infection from 8.3% in 1970 (1822 of 21878 urine samples) to 0.05% in 1986 (45 of 85053) cemented the data.5 During a ten-year field survey conducted from 1980 to 1989; 1518 human cases infected with S. haematobium were detected in this province. The incidence of infection was 0.653% in 1980, 0.021% in 1988 and 0.042% in 1989. The 20-29 year-old age group was the most infected and no sex difference was reported. In another inclusive study conducted there from 1981 to 2001 the rate of positive cases of schistosomiasis revealed a decreasing trend as follows: 1158 positive cases from 1981 to 1990; 98 cases from 1991 to 2000 and no positive cases from 2000 to 2001.

In a study in 2007 in this province, examination of all collected urine samples showed that none of the samples were found positive with urinary schistosomiasis.

This results shows an approaching step to eliminate the disease.

I believe the trend is downward as conditions improve throughout the world. Let's keep our fingers crossed to see that the trend continues to be downward.

Thank you Charles King, I think an important determining issue in decreasing transmission is the availability of praqiquantel. In 1996, Egyptian MOH adopted mass chemotherapy with this drug that was repeated every 6 month. This was followed by a steep lowering in the prevalence. Meanwhile, in response to Gilbert L'Italien, better sanitation and urbanization and availalbility of antihelminthic drugs decrease the prevalence of STH.

In Nigeria prevalence has not reduced, as intervention using mass chemotherapy is still in its infancy in many endemic communities. Coupled with population growth, poor sanitation and lack of access to safe water, Nigeria is now the most endemic country for schistosomiasis in the world. Hopefully with increasing international support for mapping of the disease and treatment, it's hoped that there would be enough political will to address the schistosomiasis control in Nigeria.

But it would be appropriate to measure that prevalence as you did for schistosomiasis . I led a small study in a remote area of Mexico and we were able to obtain a 10% random sample of stool from the children .Applying the Kato Katz method.we extimated the overall STH infection rate to be 48%(95%CI 45-56). We further identified the predominant STH (overwhelmingly ascharis). We treated all children age 2-18 and all adults (dosed according to age) with albendazole which we know is 80% effective for ascharis. We will re-test using the same sampling method later in the year. Our goal is to get to

A hidden aspect of this impressive public health campaign is the little known (2 obscure publications) discovery that a key snail predator, the exotic Louisiana crayfish is widespread in the Nile River and the Nile Delta. where there are crayfish there were no medically important snails and where there are snail intermediate hosts there are no crayfish (or there are dead crayfish due high to pollution levels) (personal observations). In other words, crayfish, as has been shown elsewhere (Kenya) are able to reduce transmission of the parasites by greatly reducing snail populations.

In Egypt, the long running and important mass drug administration (MDA) programs have taken full credit for Schistosomiasis control, but some credit may well be due to transmission reduction by the lowly crayfish. Thus when MDA programs are cut back, crayfish may be able to reduce or prevent the usual rapid recovery of disease levels. Their role is prevention of disease in Egypt deserves study and this sort of biological control may be applicable elsewhere.

Hi Armand,

I have those publications somewhere and can post the urls if anyone needs them. Here is an interesting site/program which has re- introduced this crayfish and actually not only significantly reduced the incidence of schisto, but created livelihoods for local stakeholders.

In most cases in Africa, the disappearance of this arthropod was due to irrigation schemes, thus causing exponential growth of this terrible disease as host populations of snails thrive without predators, as you state.

The program is called, 'Projet Crevette' and has been high successful

http://www.projet-crevette.org/index.php?lang=en

Thank you Armand Kuris and denise marie Marinucci, I appreciate your comment very much. I know this crayfish which is sold as a cheap shrimp like food but this is the first time to be aware of its impact on snails and transmission of schistosomiasis. However, this needs further study in addition to the impact of canal water pollution on the life cycle of the parasite

Thank you Mostafa alacrity-specific survey of crayfish, snails and if possible, human prevalence/intensity in Egypt, even in just a governourate, would be a very valuable addition to our knowledge.

Mirazid a new drug for treatment of schistosomiasis and fascioliasis in Egypt. I had past story with mirazid when described to my family in a small village located along Nile River in Qalyubia governorate for treatment of schistosomiasis. Mirazid is effective in reducing prevalence of schistosomiasis in Egypt.

Yes Nashwa but is the drug is the only tool behind the reduction of the disease ?

of course the multifarious factors are behind this

I have experience in this drug which is extracted from the stem of comphora molmol. It is used as two capsules before breakfast for 6 days with variable and conflicting results Furthermor,It is more expensive with less side effects compared to praziquantel.

http://www.ncbi.nlm.nih.gov/pubmed/20645776

Schistosomiasis is a great public health problem in Qalyubia governorate and its prevalence is higher in males than females,causes deaths in ages above 50 years due to liver cirrhosis and/or kidney dysfunction.

Great appreciation to Prof.Dr.Ahmed Massoud,Fac. Med. Al-Azhar University for his hard work in discover mirazid drug which relieve pains of patients of scistosomiasis.

yes, Shistosomiasis in Iran is a zoonotic disease that good controlled in recent years by controlling of intermediated hosts of that (snails) and antiparasitic drugs.