Intestinal Parasites: Friends, Foes and Shades of Gray

Parasite is a bad word with negative connotations. Yet, "bad things" can be good for you - and every situation is different.

About one third of people in the world carry at least one parasite in their gastrointestinal tract (the numbers reported vary from 2-4% in Japanese residing in developing countries to 6% in patients of a specialized private hospital in Saudi Arabia, 7% among individuals with mental retardation in New York, 17% in HIV patients with low CD4 counts in France, 30% in households of USA, Saudi Arabia and Turkey, 40% in Pakistan and Brasil, to over 50% in Nigeria, 50-70% in Morocco and almost 100% in Senegal). Prevalence varies between countries and within communities. Women and children appear to harbor larger numbers of parasites. But men, in general, may be less healthy than women, so the relationship between health and intestinal parasites is not as straightforward as one might think.

Let's take a look at three studies published this year.

Paper by Lukeš and co-authors (2014) suggests that intestinal parasites such as Blastocystis (single celled protozoa closely related to algae and molds) and nematodes (e.g., tapeworms or hookworms) can be actually beneficial to human health. To prove the point, Julius Lukeš even ingested  a handful of tapeworms called Diphyllobothrium latum. After more than a year with the tapeworms, which might have grown to be as long as four meters each by now, he still feels healthy and convinced that we should rethink our views of organisms that live off our bodies.

According to a Danish study (Krogsgaard et al, 2014), Blastocystis could be rare in individuals with low microbial diversity, disturbed by antibiotic treatment, inflammation, infection and diet, while common in the healthy population. Healthy individuals are more likely to carry intestinal parasites (50% vs 36%) than those with IBS and IBD. Protozoa Blastocystis and Dientamoeba were the most common parasites found. D fragilis was detected in a greater proportion of fecal samples from controls than cases (35% vs 23%; P = .03), and so was Blastocystis (22% of controls vs 15% of cases; P = .09), and combinations of parasite species (16% of controls vs 8% of cases; P = .05). D fragilis infection was more likely among those with low frequency of defecation and those having children 5 to 18 years old in the household. Blastocystis was associated with high income, increasing age, no animals in the household and drinking bottled water. These results are drawn from analyzing hundreds of individuals - 124 cases/204 controls.

Smaller and more focused studies, however, do find association between Blastocystis and IBS.

A recent French study compared the prevalence of Blastocystis among 56 IBS patients and  56 control and found that Blastocystis species are likely to couse IBS symptoms in men (prevalence was 37% in IBS sufferers vs 5% in healthy men; difference in women was not statistically significant). One of the older smaller studies that indicated possible relation between Blastocytes and IBS (Funda Dogruman-Al et al., 2009) suggested that Blastocystis don't really attack the body, it's the human organism that attacks the microbes first and the outcome is the result of defensive actions by the microbes. Obviously, symptoms do depend on many other health factors. Nourrisson and co-authors identified them as the prevalence of certain "good" bacteria. Men are more likely to get constipated when their Blastocystis leads to a significant decrease in Bifidobacterium species. On the other hand, they are doing just fine if Blastocystis causes decrease in Faecalibacterium prausnitzii - relatively good bacteria known for its anti-inflammatory properties,

Another interesting insight into the impact of a complex interplay of environmental factors on our health. Still a long way to go to understand how we interact with microbes that call us home.


REFERENCES

Lukeš J, Kuchta R, Scholz T, & Pomajbíková K (2014). (Self-) infections with parasites: re-interpretations for the present. Trends in parasitology, 30 (8), 377-85 PMID: 25033775
press release

Krogsgaard LR, Engsbro AL, Stensvold CR, Nielsen HV, & Bytzer P (2014). The Prevalence of Intestinal Parasites Is Not Greater Among Individuals With Irritable Bowel Syndrome: a Population-Based Case-Control Study. Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association PMID: 25229421

Nourrisson C, Scanzi J, Pereira B, NkoudMongo C, Wawrzyniak I, Cian A, Viscogliosi E, Livrelli V, Delbac F, Dapoigny M, & Poirier P (2014). Blastocystis Is Associated with Decrease of Fecal Microbiota Protective Bacteria: Comparative Analysis between Patients with Irritable Bowel Syndrome and Control Subjects. PloS one, 9 (11) PMID: 25365580

El Safadi D, Gaayeb L, Meloni D, Cian A, Poirier P, et al. (2014) Children of Senegal River Basin show the highest prevalence of Blastocystis sp. ever observed worldwide. BMC Infect Dis 14: 164 doi:10.1186/1471-2334-14-164.

Boorom KF, Smith H, Nimri L, Viscogliosi E, Spanakos G, Parkar U, Li LH, Zhou XN, Ok UZ, Leelayoova S, Jones MS: (2008) Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection. Parasit Vectors, 1:40 2

Krogsgaard LR, Engsbro AL, & Bytzer P (2013). The epidemiology of irritable bowel syndrome in Denmark. A population-based survey in adults ≤50 years of age. Scandinavian Journal of Gastroenterology, 48 (5), 523-9 PMID: 23506174

(2004) Intestinal parasites prevalence and related factors in school children, a western city sample--Turkey. BMC Public Health. 2004 Dec 22;4:64.

Houmsou R.S., Amuta E.U., Olusi T.A. (2010) Prevalence of intestinal parasites among primary school children in Makurdi, Benue State- Nigeria. Internet Journal of Infectious Diseaes. vol.8, 1, p.2

Schupf N, Ortiz M, Kapell D, Kiely M, Rudelli RD. Prevalence of intestinal parasite infections among individuals with mental retardation in New York State. Ment Retard. 1995 Apr;33(2):84–8

Sah, Ram; Bhattarai, Sailesh; Yadav, Satish; Baral, Ratna; Nilambar; Pokharel, Paras (2013) A study of prevalence of intestinal parasites and associated risk factors among the school children of Itahari, Eastern Region of Nepal. Tropical Parasitology, 3, 2, 140-144, DOI 10.4103/2229-5070.122143

Oman Med J. May 2011; 26(3): 182–185. doi: 10.5001/omj.2011.44 PMCID: PMC3191688 Dina AM Zaglool,1 Yousif AW Khodari,2 Zohair J. Gazzaz,3 Khalid O. Dhafar,4 Hani AS Shaker,5 and Mian U. Farooq
nt J Infect Dis. 2012 Sep;16(9):e677-9. doi: 10.1016/j.ijid.2012.05.1022. Epub 2012 Jul 6.

Prevalence of opportunistic intestinal parasitic infections among HIV-infected patients with low CD4 cells counts in France in the combination antiretroviral therapy era. Pavie J1, Menotti J, Porcher R, Donay JL, Gallien S, Sarfati C, Derouin F, Molina JM.

Jeevitha Dhanabal, Pradeep Pushparaj Selvadoss, and Kanchana Muthuswamy (2014) Comparative Study of the Prevalence of Intestinal Parasites in Low Socioeconomic Areas from South Chennai, India. Journal of Parasitology Research Volume 2014 (2014), Article ID 630968, 7 pages http://dx.doi.org/10.1155/2014/630968

Blagburn BL1, Schenker R, Gagne F, Drake J.(2008) Vet Ther. 2008 Fall;9(3):169-75. Prevalence of intestinal parasites in companion animals in Ontario and Quebec, Canada, during the winter months.

Hamada A1, Okuzawa E, Kawabuchi Y, Nishikawa T. (1998) Kansenshogaku Zasshi. 1998 Dec;72(12):1283-8. [Prevalence of intestinal parasites among Japanese residents in developing countries]. [Article in Japanese]

Hirata, T., Nakamura, H., Kinjo, N., Hokama, A., Kinjo, F., Yamane, N. et al. (2007) Prevalence of Blastocystis hominis and Strongyloides stercoralis infection in Okinawa, Japan. Parasitol Res 101: 17171719.

Javed Yakoob, Wasim Jafri, Nadim Jafri, Rustam Khan, Muhammad Islam, M. Asim Beg, and Viqar Zaman (2004) Irritable bowel syndrome: in search of an etiology: role of Blastocystis hominis Am. J. Trop. Med. Hyg., 70(4), pp. 383–385

Much ado about Bowel Movement

Want to manage your toilet metrics? There's an app for that. Actually, multiple apps - like this one recording precise GPS location of bowel events along with their shapes and odors or IBS symptom tracker and GI monitor, approved and designed by gastroenterologists.

Yet, the lists of metrics provided by these applications are not complete - no options to record color, consistency, texture, effort... And what about total time spent? According to IBS forums, it could range from seconds to ... "long enough to play a full game of Scrabble". An Israeli scientist (Sikirov, 2003) found that times "needed for sensation of satisfactory emptying" range from 50 to 130 seconds for healthy volunteers.  He plotted time and effort vs the height of toilet (41cm or 16-inch-high, 31cm or 12-inch-high toilet, and a plastic container) and found notable correlations - the shorter the better. US team (Rao et al, 2006) evaluated internal pressures of subjects with a water-filled balloon or silicone-stool in their rectum, rating their stooling sensation. As one could guess, silicone was more pleasurable and sitting was better than lying flat.  Japanese scientists (Sakakibara et al, 2010) measured hip flexon vs angularity of the  rectoanal canal and recorded abdominal pressure. Their conclusion was that squatting helps.

This is in line with observations by IBS sufferers: like this one about getting down on hands and knees and rubbing the floor with head before going to bathroom. or keeping knees elevated by placing feet on a footstool.
 
Daniel Lametti who wrote this well-researched article for Slate (Not a bunch of Internet quackery!) conducted his own squatting experiment - each morning for a week, following a bowl of corn flakes and a cup of coffee . As his 10-minute routine dropped to a minute, he was able to free an hour per week for more productive work.

The moral of the story is that we need not only switch to stand-up desks for work, but also to better-designed toilets - like this one from Japan, adjustable to several different squatting and sitting postures.

Perhaps one day such toilets will make a splash in other parts of the world.



References

Sikirov D (2003). Comparison of straining during defecation in three positions: results and implications for human health. Digestive diseases and sciences, 48 (7), 1201-5 PMID: 12870773

Rao SS, Kavlock R, & Rao S (2006). Influence of body position and stool characteristics on defecation in humans. The American journal of gastroenterology, 101 (12), 2790-6 PMID: 17026568

Ryuji Sakakibara, Kuniko Tsunoyama, Hiroyasu Hosol, Osamu Takahashi, Megumi Sugiyama, Masahiko Kishi, Emina Ogawa, Hitoshi Terada, Tomoyuki Uchiyama, & Tomonori Yamanishi (2010). Influence of Body Position on Defecation in Humans. LUTS: Lower Urinary Tract Symptoms, 2 (1), 16-21

PS. Aurametrix analyzes bowel movement and finds the best amounts and combinations of soluble and insoluble fiber, water, starch, probiotic strains,  and many other ingredients.