Software to identify and quantify pathogenic helminth eggs (National University of Mexico)

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Software to identify and quantify pathogenic helminth eggs (National University of Mexico)

Dear Colleagues,

Please find below information about our UNAM (Universidad Nacional Autónoma de México) team project to identify and quantify pathogenic helminth eggs:


Title of grant:

Software to identify and quantify pathogenic helminth eggs

Subtitle: Software to automatically identify and quantify pathogenic helminth eggs in water, wastewater, biosolids and excreta.

Name of lead organization: Universidad Nacional Autónoma de México (UNAM)

Primary contact at lead organization: Blanca Jiménez Cisneros, Ph.D.

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Grantee location: UNAM, Instituto de Ingeniería, Mexico City

Developing country where the research is being or will be tested:
Mexico, Colombia, some countries of Africa (as Namibia, South Africa, Kenya), Brazil, Philippines, India, as well as developed countries such as USA, Spain and Germany.

Start and end date:

Phase I: 02/01/2012 to 06/01/2013
Phase II: 02/01/2014 to 01/01/2016
Phase III: extended until 30 Nov. 2018

• Grant type: The Grand Challenges Explorations Grant.

Phase I: USD 100,000 ( www.gatesfoundation.org/How-We-Work/Quic...s/2011/10/OPP1044443 )
Phase II: USD 354,284 ( www.gatesfoundation.org/How-We-Work/Quic...s/2013/10/OPP1094904 )
Phase III: USD 438,268 ( www.gatesfoundation.org/How-We-Work/Quic...s/2016/11/OPP1149050 )

Short description of the project:

The following activities have been performed:

a) Integration of a library of helminth eggs images including eight different species, at three viability stages: viable eggs, non-viable eggs, and larval eggs.

b) Software development. Its functions involve detecting and labeling all visible objects in an image, using different processes (filtration, equalization, application of algorithms, etc.), and afterwards the classification of each detected objects based on shape (area, perimeter and eccentricity), and texture properties. The image library was needed to train the software on how a specific helminth egg would look like.

c) Software first validation. Comparative tests were conducted to determine the difference between software performance, and the results given by the standard identification and quantification technique performed by expert microbiologists. Most of the validation and software improvement have been done simultaneously.

The following activities are still ongoing:

a) To include additional helminth eggs species to the recognition protocol.
b) To finish the lab validation so all the objectives can be achieved.
c) To perform international peer-labs test and validation.
d) To develop a user friendly software that may be widely distributed.
e) To find a proper distribution channel that benefits target users (mostly) in developing countries.

Goal(s) Phase I:

To provide an image processing tool to reduce the cost and time consumed by the identifying and quantifying of helminth eggs.

Objectives (Phase I):

a) Setting a workstation: the first task to begin the project was to put a microscopic image processing workstation.

b) Generating helminth eggs image library: with the workstation ready, several helminth eggs images were acquired. The species used for this objective were selected, based on their medical importance and worldwide ubiquity.

c) Developing identification software: a comparative study of the available recognition protocols and image processing techniques was performed.

d) Increasing the number of involved species of helminth eggs: additional species of helminth eggs were selected regarding the difficulty level of identification and the widespread presence.

e) System improvement: New image processing tools and changes were applied to the software. At this point a series of filters were added for image processing.

f) System validation: The validation was made using wastewater samples of three different quality levels.


Goal(s) Phase II:

To distribute this tool worldwide, and ensure mainly that those regions that have limited resources to perform wastewater, sludge, biosolids and excreta quality assessments have easy access to this tool.


Objectives (Phase II)

a) To increase the sensibility of the identification system when dealing with high solids content water (class III or raw wastewater) and establish the protocol for this case.

b) To validate the software to detect and quantify different genera of helminth eggs from samples of different water qualities including wastewater and greywater, and also from sludge, biosolids and excreta samples.

c) To include additional helminth eggs species to the recognition protocol.

d) To validate the system with international partners.

e) To test the system with Mexican partner labs which are certified in the standard technique to start local distribution.

f) To obtain a patent for the system.

g) To launch a worldwide distribution strategy.

h) To develop an easy-to-use platform of the software and the distribution strategy to reach the final users.

i) To test the last version and establish the distribution strategy.


• Research or implementation partners: Fernando Arámbula, Ph.D. CCADET, UNAM.

• Links, further readings:

Documents in SuSanA library: www.susana.org/en/resources/library/details/2048

Results to date:

a) So far, the system:

• is able to process images with a 99% of specificity, which means that it can distinguish between helminth eggs and other objects with a 99% of reliability.

• has also been validated to yield a 90% reliability to distinguish among five different helminth genera from water samples with a less than 150 mg/L of total suspended solids.

• is being tested and validated to be used for different samples (water, sludge, biosolids and excreta), so the protocol for each type of sample will be properly established, which gives the system a great versatility.

• is including additional species of helminth eggs species to the recognition protocol.

• is also aiming to take third party trials before the final version is delivered, and afterwards, to build the most suitable platform to develop a user friendly system, so we may focus on the distribution strategy.

• The patent is pending, but the methodology is already safeguarded.

• To develop an easy-to-use platform of the software and the distribution strategy to reach the final users.

• Current state of affairs: The developing team is in direct contact with international peer-labs interested on validating the software.

• Biggest successes so far: Platform ready to distinguish among eight genera of helminth eggs with 90% of reliability and 99% specificity for water samples.

• Main challenges/frustration: To broaden the software capability to analyze wastewater with higher content of total suspended solids, and develop the protocol for biosolids and excreta.


In the following paragraphs it is presented a short summary about the first results:

Software to identify and quantify pathogenic helminth eggs

The analytical technique used to identify and quantify helminth eggs, besides its time consuming nature, involves a key step in which highly trained laboratory technicians have to properly identified different types of eggs and count them. This step is the main source of errors impacting the reliability of the fulfillment of the norms or the performance of a treatment process. To overcome this problem, this project focused on the development of a software to identify and quantify different species of helminth eggs in samples.

Helminths (parasitic worms) are the origin of health risks associated with the lack of or a deficient sanitation service, the use of polluted water for irrigation, and the disposal of excreta or contaminated sludge in soils. Helminths are transmitted to humans through their eggs which are highly dangerous due to their low infectious dose, their high persistence in the environment, and their high resistance to inactivation processes. Helminthioses are endemic in Africa, Latin America and East Asia, provoking diarrhea, undernourishment, and anemia. It is estimated that around 350 million people are infected worldwide, especially children between 5 and 15 years of age.

For these reasons, since 1989, the WHO and since then many other organizations have set guidelines of standards limiting the content of helminth eggs in wastewater (1 egg/L or less), greywater, and sludge (1 egg/gTS or less) when used for agricultural irrigation. The limit values always involve the need to use a highly accurate analytical procedure. Nevertheless, it is always available, notably in developing countries, limiting the possibility to enforce the standards in the countries where it is more needed.

Given the above explained complexity to accurately analyze biological images to identify and count helminth eggs, it was decided to develop an image processing software in order to identify and count eggs from photographs taken on a microscope of a processed sample of wastewater, greywater, excreta or sludge. The developed software comprises two steps: the first is to detect and label all visible objects using different processes (filtration, equalization, application of algorithms, etc.). The second step is to classify each of the detected objects based on shape (area, perimeter and eccentricity) and texture properties (energy, mean gray level, contrast, correlation and homogeneity) as one the helminth eggs specie recognizable by the software.

Currently, the software is able to identify five species (Ascaris lumbricoides as fertile and unfertile, Trichuris trichiura, Toxocara canis and Taenia saginata) and in a next version three species more will be included (Hymenolepis nana, Hymenolepis diminuta and Schistosoma mansoni). In total, 360 images of the different species were used to set the range values for each classification property.

The software has 90% sensibility (ability to identify one specie among the others in a wastewater sample) and 0.99 specificity (potential to distinguish an egg from any other objects in a wastewater sample). Currently, the software is under adaptation to process excreta and sludge samples. Based on experimental tests the use of the software reduce the identification and quantification time response. This represents savings on the time of highly trained personnel per analysis. In addition, the reliability of the analysis increases by 90%.

More information about the pathogens inactivation is included in the next two files. The first is a paper about the synergy with different environmental conditions to inactivate helminth eggs in sludge samples, and the second one is a PDF presentation in the Disinfection World Congress (paper is in press) about the inactivation of different microorganisms.

Viability of six species of larval and non-larval helminth eggs for different conditions of temperature, pH and dryness
C. Maya, F.J. Torner-Morales, E.S. Lucario, E. Herna´ndez, B. Jime´nez*

Water Research 46 (2012), 4770 - 4782
dx.doi.org/10.1016/j.watres.2012.06.014

A b s t r a c t

Helminth eggs are the most difficult biological parasites to inactivate in wastewater and
sludge. In developing countries, in particular, they are present in high concentrations and
are the cause of many diseases that impact seriously on the human population. The
process conditions for affordable inactivation are very variable, leading to different inactivation
efficiencies. Temperature, dryness, pH and the developmental stage of the eggs
must be taken into consideration to achieve complete inactivation. The objective of this
research was to study the inactivation of six species of larval and non-larval helminth eggs
of medical importance in developing countries under controlled conditions of temperature,
pH, dryness and contact time. Results showed considerable differences in inactivation
conditions among helminth eggs and a high level of resistance was confirmed for the eggs
of Ascaris lumbricoides and Ascaris suum. The appropriate conditions for inactivation of all
types of eggs were found by applying combinations of pH, temperature and dryness. At
45 C it was possible to inactivate all species with a pH of 5.3 and 90% dryness within 6
days. If alkalization was applied, a pH of 12.7 was sufficient over 19 days at the same
conditions of dryness and temperature. From these results it is proposed that both Ascaris
spp. and Taenia solium may be used as indicators of biological contamination in wastewater
and sludge.


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Blanca
Water Treatment and Reuse Team, UNAM
Instituto de Ingeniería (Engineering Institute)
Universidad Nacional Autónoma de México, Mexico City.

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Re: Wanting a better way to test pathogen inactivation? Us too! Can you help me crowdsource a better way?

Dear partner, I am including a PowerPoint file regarding our work on "Software to identify and quantify pathogenic helminth eggs".

Blanca
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  • In the Global Development GCE Phase II, sponsored by Bill & Melinda Gates Foundation, we are the Water Treatment and Reuse Team. Our main project is to develop a software that will identify and quantify helminth eggs.
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Dear all,

The Global Development Phase II, sponsored by Bill & Melinda Gates Foundation, is focused on the elaboration of an automatic image analysis software that performs the identification and quantification of helminth eggs of a processed sample of wastewater, sludge or excreta. Alongside our investigation, we work to train people through our academic programs such as social services and undergraduate, MSc and PhD.

An example of this is the MSc thesis developed in Phase I and for which the degree examination was done at the beginning of 2014:

Pérez Sánchez, J. D. (2013). Identificación y cuantificación automática de huevos de helmintos en muestras de agua residual (in Spanish) - Automatic identification and quantification of helminth eggs in wastewater samples. MSc thesis, Universidad Nacional Autónoma de México (UNAM), Mexico.

For those of you who are interested in our software to quantify helminth eggs in wastewater samples, you might find this MSc thesis useful. It is in Spanish, but there is an English summary. You can find the full text on the link below:

susana.org/lang-en/library?view=ccbktypeitem&type=2&id=2052

Here is a section of the English summary:

Given the complexity of biological automatic image analysis, we performed a comparative study of protocols for image processing techniques applicable for this study. The development of automatic identification technique used 360 images of different species (Ascaris lumbricoides (fertile and infertile), Hymenolepis nana, H. diminuta, Schistosoma mansoni, Taenia sp., Toxocara canis and Trichuris trichiura), which allowed the training of the system and establishment of a range of values for each property classification.

System validation is always performed with residual water samples, we commonly classified it in three different qualities based on the total suspended solids (TSS). Class I was water with 150 mg / L (TSS), typical of untreated wastewater. This allowed us to validate the results according to the amount of solids present in water. For Class I and Class II, results were obtained identifying specificity 0.99 and 0.98, respectively, indicating that the system is able to distinguish between significant accuracy helminth egg and different objects. For the same quality of water, yielded a sensitivity of 0.83 and 0.80, respectively, indicating the system's ability to identify a species among other exceeds 80%. The Class III identification efficiency was considerably lower (15%) than samples I or II. So in the current conditions of the system, must be carried out a prior dilution of the samples before identification and quantification through software.

The advantages of the developed system versus the traditional technique are: a) No specific skills required for the recognition of the species. b) Samples with different amount of total suspended solids can be identified in approximately 10 minutes against three hours or more of the traditional technique. c) The initial cost of the software is 30,000 compared to 20,000 dls of the traditional technique, but the operating cost per sample is less in the case of software with 2 dlls per sample versus 10 - 35 dlls for traditional technique. Regarding the specificity and sensitivity of the developed software, both features exceed 80%, while the traditional technique depends on previously acquired human skills.

If you have questions, please don’t hesitate to ask.

Regards,

Water Treated and Reuse Team (WTR Team)

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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Hello Blanca
Thanks for the news on automated image analysis of Helminth eggs and the Perez Sanchez thesis. Is this method now being used routinely in Mexico?

I noticed in your article from 2009 "Helminth ova control in wastewater and sludge for advanced and conventional sanitation" ( www2.gtz.de/Dokumente/oe44/ecosan/en-hel...-wastewater-2007.pdf ) you write that there are some 5 million people with Helminth infections. How does this compare with the estimated number by WHO which is so much higher at 2 billion. www.who.int/mediacentre/factsheets/fs366/en/ Could be you were referring to Ascaris only?

My thesis is that hygiene and treatment of faeces remain so poor across the developing world that this monster has just kept growing for the past 50 years even with some concerted deworming programmes. This is by far the single most widespread public health problem dwarfing all others.

Easier and automated monitoring may help lead to more measurements to better determine risk. Hopefully this will motivate communities to push for more stringent sanitation and hygiene.
Arno Rosemarin PhD
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  • In the Global Development GCE Phase II, sponsored by Bill & Melinda Gates Foundation, we are the Water Treatment and Reuse Team. Our main project is to develop a software that will identify and quantify helminth eggs.
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Hello Arno,

You have reason about the 5 million, this does not correct, the "precise" number is 3,500 million (3.5 billion).

We included a table with information about this number of worldwide´s infections by helminthiases.

In this moment we are working with the validation of the final system.

Regards and thanks for your note.

WTR Team

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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Thanks Blanca. That half of humanity is infected with Helminth worms says to me that this the is by far our largest single public health problem. But so little awareness and discussion. It isn't killing people off (obviously this is the nature of parasites to keep their hosts alive) but it is preventing these individuals from having normal healthy lives. It also is an indicator that we don't have control over this group of parasites including the transfer vectors from food, water, air, contact, etc. With this level of exposure what then are the possible impacts of other pathogens that may become present in sanitation, water and food systems? The resistance of populations to withstand epidemics must be lower with this widespread burden level of parasites. What research group in Mexico is looking at the synergistic effects?

When it comes to deworming a community, this is much more than a challenge for medical doctors. All the "other" vectors and sources need to be covered including soil surfaces, yards, toilets, septic tanks, sewer pipes, etc. So practices like open defecation, dumping of collected faecal sludge in open areas and ditches and discharge of untreated wastewater, septage and sewerage are all suspected vectors of transmission.

Add pathogens like Cholera to these rather "open" systems and the risk of widespread epidemics can be explained. What then are the risks of Ebola spreading among members of communities knowing how dysfunctional these systems are.
Arno Rosemarin PhD
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  • In the Global Development GCE Phase II, sponsored by Bill & Melinda Gates Foundation, we are the Water Treatment and Reuse Team. Our main project is to develop a software that will identify and quantify helminth eggs.
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Dear Arno:

As you can see, the problem of helminthes is not an easy one, and I would add that even though they are killing all their hosts, they still may cause death in severe cases. The Bill and Melinda Gates are aware of the importance of helminthes worldwide and thus they are working hard to implement solutions on different aspects (detection, treatment, control, etc.).
We are not aware of studies that report the effect of helminthes on immunity for other diseases but we suppose that they may increase the risk of infection due to other microorganisms. We also agree that to break the cycle of this type of parasites, sanitation is not sufficient to control them, it should be accompanied by deworming and educations programs that reduce the risk of people exposed to wastewater and sludge.

With respect to Cholera, the agent responsible of this disease is a bacterium that is not as resistant as helminthes to conventional treatment processes, however, if the infection is not treated on time it may cause death. On the other hand, Ebola is a disease that we are not familiar with and thus would not like to emit an uninformed opinion.

Best regards,
Water Treatment and Reuse Team, UNAM
Instituto de Ingeniería (Engineering Institute)
Universidad Nacional Autónoma de México, Mexico City.

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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Dear Cati from the WTR Team at UNAM,

I am learning so much about helminth infections from you in this thread, it is really great. Thank you very much!

I just have a small question about the table that you attached above (I attach a modified version of the table, that you sent me by e-mail, below). Maybe it is a silly question.
But you have listed the infections with various types of intestinal worms (helminths) and then added them up. In sum it came to 3.5 billion people - half the global population!
But could it be that the same person is infected with two more more different helminth species, in which case the sum of people infected should be lower? Or is it the case of "once infected with worm A then worm B takes a different host"?)

By the way for the interest of others: Cati and I are currently looking at how to improve the relevant Wikipedia pages on this complex topic, in particular these ones:
en.wikipedia.org/wiki/Helminths
en.wikipedia.org/wiki/Helminthiasis
en.wikipedia.org/wiki/Soil-transmitted_helminthiasis
en.wikipedia.org/wiki/Ascaris
en.wikipedia.org/wiki/Ascariasis

The problem already starts with the naming convention, some people say helminthosis, others say helminthiasis (Cati explained to me that the -osis version would be the preferred one according to some experts who have published about this).

If anyone knows any people who have a special interest in intestinal worms and sanitation, please point them my way (or point them to this thread here) as I need any additional help I can get in getting the information on Wikipedia (which is already very good) in an even better shape (i.e. with more explanations regarding what improved sanitation could do to reduce these infections).

Regards,
Elisabeth


[End of Page 1 of the discussion]
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  • TeamWTR
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  • In the Global Development GCE Phase II, sponsored by Bill & Melinda Gates Foundation, we are the Water Treatment and Reuse Team. Our main project is to develop a software that will identify and quantify helminth eggs.
  • Posts: 18
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

[Start of Page 2 of the discussion]

Dear Elisabeth

Actually, one person can be infected with more than one species, although it is not common since many species are endemic of certain areas, but the number in the table refers to number of people infected, so a person infected with more than one species would still count as one.

Regards, Cati.
Water Treatment and Reuse Team, UNAM
Instituto de Ingeniería (Engineering Institute)
Universidad Nacional Autónoma de México, Mexico City.

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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Dear Cati,

Ah, I didn't know that. So it is likely that people in country X or in region X are infected with one type of helminth, whereas in another country or region it will likely be another type? These helminths are therefore not really "competing" with each other in the same region?

I am sorry, but I still have a question about the table (see my previous post above where I attached it).
I have transferred the figures in Excel and made 2 columns: one with the lower estimate and one with the higher estimate.

Where you wrote "several millions" for Trichostrongylus orientalis I made it 3-6 million.

When I sum that up I get 3.02 billion for the lower estimate and 3.4 billion for the higher estimate. How did you get to 3.5 billion? Is there a separate reference for that?

Also if I simply sum up the figures in the table then I would assume that each person is only infected with one type of worm, not with two. Therefore, the real estimate should be lower than 3 billion?

Where am I going wrong?

Edit:
I just read on Wikipedia on this page: en.wikipedia.org/wiki/Trichuriasis
which sent me to this reference: www.thelancet.com/journals/lancet/articl...(06)68653-4/fulltext

which said:

The three main soil-transmitted helminth infections, ascariasis, trichuriasis, and hookworm, are common clinical disorders in man. The gastrointestinal tract of a child living in poverty in a less developed country is likely to be parasitised with at least one, and in many cases all three soil-transmitted helminths, with resultant impairments in physical, intellectual, and cognitive development.



By the way: What everyone else doesn't know: Cati has been a star in providing me with materials to include in the Wikipedia page on helminths, helminthiasis and eight key helminth types.

She has submitted excellent photos of helminth ova, ova dividing, larvae hatching and so forth. See one of her collages here:

File Attachment:
Collage Helmith eggs by Sustainable sanitation , on Flickr

See another one of different types of ova here:

File Attachment:
Collage of various helminth eggs by Sustainable sanitation , on Flickr

Cati is this you here hard at work:?

File Attachment:
Identification and quantification of helminthes eggs by Sustainable sanitation , on Flickr

See all the rest of her photos (in three sets) here:
www.flickr.com/photos/gtzecosan/collections/72157609450504284/

Check out our improved Wikipedia article on helminthiasis:
en.wikipedia.org/wiki/Helminthiasis
(more work still remains to be done)

I am still trying to get hold of photos showing the damage that helminths can do to the human body. I have tried all sorts of avenues (like HIFA Dgroup) but no success so far. I am thinking are no doctors taking photos of this infection which affects up to 3.5 billion people??

Here is one but it's an old one (for Guinea worm which is nearly eradicated in most country thanks to the Carter Initiative):

File Attachment:
MIS67-1563-3 by medicalmuseum , on Flickr

If anyone has such photos and is willing to share them please bring them to my attention. And if anyone knows doctors working with people likely to be infected please check with them if any photos could be taken (with the consent of the patients of course).

Regards,
Elisabeth

P.S. With the restructuring of categories, we now have a sub-sub-category specifically dedicated to helminth infections and helminth ova measurements, see here:
forum.susana.org/forum/categories/159-in...nth-ova-measurements
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  • TeamWTR
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  • In the Global Development GCE Phase II, sponsored by Bill & Melinda Gates Foundation, we are the Water Treatment and Reuse Team. Our main project is to develop a software that will identify and quantify helminth eggs.
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

I have updated the table with more recent data, the results add nearly 3.5 billion. Although I still have my doubts about Taenia In my opinion the number of infections is very low, I am pretty sure they cause more infections I just cannot find a source, I could find this cite that says that it is widely distributed worldwide.

In developing countries geohelminth, infections are of major concern. The eggs of, especially, Ascaris and Taenia are persistent in the environment and are therefore regarded as an indicator and index of hygienic quality.


Reference:
WHO (2006) Safe Use of Wastewater Excreta and Greywater, Vol 4, p. 32


I am attaching a file with the table and added the total results at the bottom.



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Actually one person can be infected with more than one helminth. The important thing here is what you are considering for your results, if you are talking about number of infections then a person that is infected with, let’s say Ascaris and Hookworms and would add to the total of both results. If you are talking about people infected (in general) then it would count as one, or people infected with a certain parasite would add to that result. In this case, since the results are reporting number of infections indeed a person infected with more than one species would add to both results. This is usually how results are reported.

However depending on the region a person lives, and his lifestyle it is more susceptible to certain species of helminth. Some occupations demand people to be in contact with specific infective agents of helminth species, specially people dedicated to agriculture and also consumers in certain countries that use wastewater for irrigation have a high probability of being infected.
In the document attached is a chart that shows the distribution of Ascaris, Trichuris and hookworms worldwide. Also in the table where the total infection results are reported there is a column, that specifies the endemic regions of each species. So by knowing this information people can know if they are in risk of a parasitic infection.

Two different helminth species in the same host do not interfere with their lifecycle so it is not considered that they compete.

I am glad to provide you with photos, but no, it is not me in the picture she is Dr. Blanca Jimenez. Thank you very much for uploading our photos.

Regards,
Cati.
Water Treatment and Reuse Team, UNAM
Instituto de Ingeniería (Engineering Institute)
Universidad Nacional Autónoma de México, Mexico City.

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  • Elisabeth
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  • I'm passionate about SuSanA's role in the WASH sector since about 2005. I'm a freelance consultant since 2012 (former roles: program manager, lecturer, process engineer for wastewater treatment plants)
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Re: Software to identify and quantify pathogenic helminth eggs (University Universidad Nacional Autónoma de México (UNAM), Mexico)

Dear Cati,

OK, now it's clearer, thanks a lot. So we are talking about 3.5 billion infections with helminths, not 3.5 billion infected people.
If we assume that a person has 1-2 types of helminths at a given time (so say: 1.5), then we could estimate that 2.33 billion people are infected with helminths worldwide (=3.5 divided by 1.5).

This matches quite well with the two estimates given in the Wikipedia article about helminthiasis of 1.5 - 2 billion people
( en.wikipedia.org/wiki/Helminthiasis#Infection_estimates )


And I have a comment to make about the graph that you had attached, i.e. this one:



Once again, India sticks out like a sore thumb above all other countries! I thought at first, yes that's because the population in India is so huge. But then I realised that the values on the y-axis have already been adjusted per inhabitant (or per 10^5 inhabitants to be precise)! So this is really bad for India.

Another observation is that hookworms are more prevalent than the other two worm species. I always thought that Ascaris is the main helminth species worldwide? Or is it just that in sanitation literature it is used so much as a "model" for all helminths and this has skewed my impression of its importance?

I actually had to double check what hookworms are. Of course I went to our trusted Wikipedia pages (which I have been working on improving together with James and Cati).
See:
en.wikipedia.org/wiki/Hookworm

Hookworms is actually a summary term for three individual species:

Three species of hookworms commonly infect humans: Ancylostoma duodenale, Necator americanus and Strongyloides stercoralis


If you feel lost with all these types of worms (and there are actually thousands of different types! Mind boggling), then do take a look at the improved Wikipedia page here:

en.wikipedia.org/wiki/Helminthiasis#Most_common

or here:

en.wikipedia.org/wiki/Helminthiasis#Neglected_tropical_diseases

This is stuff that I recently added to Wikipedia. If anyone spots any mistake, please tell me or edit the page yourself, please.

And I recently had a small break-through in my hunt for photos of helminthiasis: I got permission to use this image (which is from South Africa) in a Wikipedia page:



The photo caption says: This piece of intestine, blocked by worms, was surgically removed from a 3-year-old boy at Red Cross Children’s Hospital. The child survived, but no child should be subjected to such an easily preventable condition. Photo: Allen Jefthas

I am still looking for more (clinical) photos. If 2 billion people are infected with worms, there have to be more clinical photos around somewhere on someone's PC...

Regards,
Elisabeth
Head moderator of this Discussion Forum
(with financial support from WSSCC, now SHF)

Dr. Elisabeth von Muench
Independent consultant located in Brisbane, Australia
This email address is being protected from spambots. You need JavaScript enabled to view it.
Twitter: @EvMuench
Founder of WikiProject Sanitation: en.wikipedia.org/wiki/Wikipedia:WikiProject_Sanitation
My Wikipedia user profile: en.wikipedia.org/wiki/User:EMsmile
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