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

Digestive Diagnostics: Portable, Wearable, Insideable

Next sensors will be in you, said a recent popular article. And some of them will monitor your digestive system.

Accurate monitoring of digestion is hard. There are apps and high tech gadgets for that - like a fork that monitors eating speed or a watch that counts bites, but neither of them can provide a continuous and objective measures of what exactly is eaten and how it affects the digestive system.

Thanks to wonders of modern technology, cows now have a device that can monitor the effects of food on their digestive system. Well Cow bovine health monitor, an inch thick capsule almost as long as human hand, can be swallowed by a cow and measure the rumen pH and temperature within the digestive system every 15 minutes. It then transmits the data to a Bluetooth collar around the cow’s neck. This data can help to monitor the healthiness of cow's food intake, to predict its gas-forming potential in the short term, make sure it will lead to a high quality milk or prevent the development of health issues such as acidosis or infertility in the long term. The device can last between 80 to 100 days inside the cows.

A smaller vitamin-sized device (1mm x 26mm with weight less than 4 grams) was recently approved for use in humans. This ingestible pill camera - PillCamSB -  can monitor pressure, pH and temperature, gastrointestinal motility, lesions, ulcers, early signs of tumors and bleeding within the small bowel. FDA approved it for patients who have experienced an incomplete colonoscopy, as its lower-resolution-imaging can't completely replace the procedure.

Food we eat and drugs we take can communicate from our insides too - Ingestible Event Maker sensor - size of a grain of sand - can be attached to any pill or a food item.

Perhaps in the future we could rely on "insideables" to monitor our diet and automatically generate recommendations on what to eat and what to avoid?

According to a song, The Future's So Bright Gotta Wear Shades.

REFERENCES

Kiourti, Asimina. (2014). Implantable and ingestible medical devices with wireless telemetry functionalities: A review of current status and challenges. Bioelectromagnetics, 35 (1), 1-15 DOI: 10.1002/bem.21813

Hoskins, S.; Sobering, T.; Andresen, D.; Warren, S. (2009). Near-field wireless magnetic link for an ingestible cattle health monitoring pill Engineering in Medicine and Biology Society, 2009. EMBC 2009. Annual International Conference of the IEEE DOI: 10.1109/IEMBS.2009.5332812

Wong WM, Bautista J, Dekel R, et al. Feasibility and tolerability of transnasal / per-oral placement of the wireless pH capsule vs. traditional 24-h oesophageal pH monitoring – a randomized trial. Aliment Pharmacol Ther. 2005; 21(2): 155-163.

Hirono I, Richter JE. Practice Parameters Committee of the American College of Gastroenterology. ACG practice guidelines: esophageal reflux testing. Am J Gastroenterol. 2007; 102(3): 668-685.

Teunissen LP, de Haan A, de Koning JJ, Daanen HA. Telemetry pill versus rectal and esophageal temperature during extreme rates of exercise-induced core temperature change. Physiol Meas. 2012 Jun;33(6):915-24. doi: 10.1088/0967-3334/33/6/915. Epub 2012 May 3.