Current world status of Balantidium coli

Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections

Over the past few decades, nucleic acid-based methods have been developed for the diagnosis of intestinal parasitic infections. Advantages of nucleic acid-based methods are numerous; typically, these include increased sensitivity and specificity and simpler standardization of diagnostic procedures. DNA samples can also be stored and used for genetic characterization and molecular typing, providing a valuable tool for surveys and surveillance studies. A variety of technologies have been applied, and some specific and general pitfalls and limitations have been identified. This review provides an overview of the multitude of methods that have been reported for the detection of intestinal parasites and offers some guidance in applying these methods in the clinical laboratory and in epidemiological studies.

A case report of an uncommon parasitic infection of human balantidiasis

Balantidium coli, a large, ciliated pathogen, is known to cause balantidiasis in humans. We report a case of B. coli infection in a 37-year-old male with tuberculosis and presenting with fever, anorexia, mild abdominal pain, and episodes of loose stools for 1 week.

Urinary infection due to Balantioides coli: a rare accidental zoonotic disease in an addicted and diabetic young female in Iran

BACKGROUND

Balantiosis, a rare zoonotic infection resulting in dysentery, is caused by the large ciliated protozoan parasite Balantioides coli. Humans acquire this organism via the faecal-oral route. Very rarely, extraintestinal infections can occur in the urinary tract system. There are very few case reports of urinary balantiosis in humans.

CASE PRESENTATION

Here, an interesting case of urinary balantiosis in a 35-year-old addicted woman with multiple health problems including spontaneous abortion and diabetes is reported. Her midstream urine sample, collected while all sterile precautions were being taken, demonstrated B. coli along with Trichomonas vaginalis and bacteria. B. coli was identified by its characteristic morphology and rapid rotary motility in the urinary tract, which is an abnormal site for invasion by this parasite.

CONCLUSION

To the best of our knowledge, this is only the eighth case described in literature in which B. coli was detected in urine sediment; it is reported for its rarity and for future reference.

Urinary balantidiasis: A rare incidental finding in a patient with chronic obstructive pulmonary disease

Balantidiasis is a rare zoonotic disease in humans. Balantidium coli is the causative ciliated protozoan. We present a case of urinary balantidiasis in a patient having chronic obstructive pulmonary disease (COPD) who was on steroids for a long time. He has no symptoms of bowel or urinary involvement. We are reporting this case because of its rarity in human urine and also for future references.

Gastrointestinal parasites of swine raised in different management systems in the State of Rio de Janeiro, Brazil

Abstract: From 2012 to 2013 were surveyed gastrointestinal parasites from pig farms located in different municpaliyies in the state of Rio de Janeiro. Fecal samples from 790 pigs were collected from the rectum on 88 family farms and 702 farms with industrial production. The samples were subjected to Faust et al., Sheather, Ritchie, Lutz and direct examination faecal techniques. The estimated parasite prevalence was 93.1% in family farms and 59.1% in industrial farms. Balantidium coli, coccidia and Entamoeba sp. were the parasites with the highest frequencies, and the male and female reproductive categories and fatteners pigs the most infected (p<0.05). Trophozoites of B. coli were most evident in stool samples from semi-solid followed by solid and diarrheal consistencies. Strongyles eggs and Trichuris suis have been detected exclusively in family farms. Ascaris suum eggs and Strongyloides ransomi showed low frequency. The high degree of parasitism, especially protozoa, indicates the need to reassess the management of pigs in both types of production.

Endoparasite survey of free-swimming baleen whales (Balaenoptera musculus, B. physalus, B. borealis) and sperm whales (Physeter macrocephalus) using non/minimally invasive methods

A number of parasitic diseases have gained importance as neozoan opportunistic infections in the marine environment. Here, we report on the gastrointestinal endoparasite fauna of three baleen whale species and one toothed whale: blue (Balaenoptera musculus), fin (Balaenoptera physalus), and sei whales (Balaenoptera borealis) and sperm whales (Physeter macrocephalus) from the Azores Islands, Portugal. In total, 17 individual whale fecal samples [n = 10 (B. physalus); n = 4 (P. macrocephalus); n = 2 (B. musculus); n = 1 (B. borealis)] were collected from free-swimming animals as part of ongoing studies on behavioral ecology. Furthermore, skin biopsies were collected from sperm whales (n = 5) using minimally invasive biopsy darting and tested for the presence of Toxoplasma gondii, Neospora caninum, and Besnoitia besnoiti DNA via PCR. Overall, more than ten taxa were detected in whale fecal samples. Within protozoan parasites, Entamoeba spp. occurred most frequently (64.7%), followed by Giardia spp. (17.6%) and Balantidium spp. (5.9%). The most prevalent metazoan parasites were Ascaridida indet. spp. (41.2%), followed by trematodes (17.7%), acanthocephalan spp., strongyles (11.8%), Diphyllobotrium spp. (5.9%), and spirurids (5.9%). Helminths were mainly found in sperm whales, while enteric protozoan parasites were exclusively detected in baleen whales, which might be related to dietary differences. No T. gondii, N. caninum, or B. besnoiti DNA was detected in any skin sample. This is the first record on Giardia and Balantidium infections in large baleen whales.

Study of the gastrointestinal parasitic fauna of captive non-human primates (Macaca fascicularis)

The aim of this study was to examine helminths and protozoans in cynomolgus macaques (Macaca fascicularis) imported from registered breeding facilities in China and their relation to health risks for non-human primate handlers in biomedical research centers and in breeding facilities. Fresh fecal samples were collected from a total of 443 M. fascicularis and analyzed by copromicroscopical analysis, immunoenzymatic, or molecular assays. As to helminths, whose eggs were shed in 2.03% of the samples, Trichuris and Oesophagostomum were the only two taxa found, with low prevalence and low eggs per gram (EPG) values. Protozoans were more frequently detected (87.40%), with Entamoeba coli (85.19%) and Endolimax nana (79.26%) as the most prevalent species shed. Other parasites found by fecal smear examination were uninucleated-cyst-producing Entamoebas (78.52%), Iodamoeba bütschlii (42.96%), and Chilomastix mesnili (24.44%), while cysts of Balantidium coli (22.2%) were only observed by sedimentation. No coproantigens of Giardia duodenalis, Cryptosporidium spp., and Entamoeba histolytica complex were detected. Blastocystis sp. infection was noticed in 87.63% of macaques by PCR. These cynomolgus monkeys were infected with many subtypes (ST1, ST2, ST3, ST5, and ST7), where the predominant Blastocystis sp. subtypes were ST2 (77.5%), followed by ST1 (63.5%). Data collected confirmed the presence of potentially zoonotic parasites and a high parasite diversity, suggesting the need for appropriate and sensitive techniques to adequately control them and related health risks for handlers of non-human primates in biomedical research centers and in breeding facilities.

Parasitic colitis

Over one billion people worldwide harbor intestinal parasites. Parasitic intestinal infections have a predilection for developing countries due to overcrowding and poor sanitation but are also found in developed nations, such as the United States, particularly in immigrants or in the setting of sporadic outbreaks. Although the majority of people are asymptomatically colonized with parasites, the clinical presentation can range from mild abdominal discomfort or diarrhea to serious complications, such as perforation or bleeding. Protozoa and helminths (worms) are the two major classes of intestinal parasites. Protozoal intestinal infections include cryptosporidiosis, cystoisosporiasis, cyclosporiasis, balantidiasis, giardiasis, amebiasis, and Chagas disease, while helminth infections include ascariasis, trichuriasis, strongyloidiasis, enterobiasis, and schistosomiasis. Intestinal parasites are predominantly small intestine pathogens but the large intestine is also frequently involved. This article highlights important aspects of parasitic infections of the colon including epidemiology, transmission, symptoms, and diagnostic methods as well as appropriate medical and surgical treatment.

Isolation and maintenance of Balantidium coli (Malmsteim, 1857) cultured from fecal samples of pigs and non-human primates

Balantidium coli is a protozoa that can determine dysentery in humans, pigs and non-human primates having zoonotic potential. The lack of standardization in isolation and maintenance hinders the development of research on its biology and epidemiology. This study is aimed to standardize the isolation and maintenance of this parasite from animal feces, in culture medium, Pavlova modified. From 2012 to 2014, 1905 fecal samples were collected from captive animals of Rio de Janeiro. Were selected for isolation samples with a minimum of 10 trophozoites and/or 30 cysts of B. coli, totaling 88 pigs, 26 Cynomolgus and 90 rhesus macaques. In the presence of cysts, the sample was homogenized in saline solution, 500 μL was removed and inoculated into culture medium. The material that contained trophozoites the inoculum was made from 240 μL of fecal solution. All inoculate tubes with the subcultures were kept at 36°C, and sterile rice starch was always added to the medium. The parasites isolate from pigs, 34%, and from Cynomolgus 38.4% were maintained in vitro for a period of more than 24 months. These procedures proved to be adequate for isolation and maintenance of B. coli from different animals, they were found to be inexpensive and easy to perform.

Occurrence and molecular analysis of Balantidium coli in mountain gorilla (Gorilla beringei beringei) in the Volcanoes National Park, Rwanda

Cysts morphologically resembling Balantidium coli were identified in the feces of a mountain gorilla (Gorilla beringei beringei). Confirmatory PCR and sequencing revealed two distinct B. coli-specific sequences (ITS-1, sub-types A0 and B1). This represents the first report of B. coli in this species, raising the possibility of infection from a reservoir host.

Balantidium coli and other gastrointestinal parasites in captives non-human primates of the Rio de Janeiro, Brazil

BACKGROUND

Parasites are agents of diarrhea in captive non-human primates (NHP). To broaden information about those etiological agents in captive animals in Brazil, gastrointestinal parasites in captive NHP were researched in nurturing Centers of Rio de Janeiro State.

METHODS

Fecal samples were collected from primates, of which 960 came from the Research Center (Cecal/Fiocruz) and 115 from the Primate Center (CPRJ/Inea). The study involved species of the New World (NW) primates and of the Old World (OW).

RESULTS

The estimated prevalence was 56.7%, of which 91.3% presented protozoans and 7.4% presented helminths. Statistical difference between the nurturing centers occurred in the overall value of parasitosis and in the isolated frequency of Balantidium coli and Entamoeba sp., especially in the samples of OW primates living in Cecal.

CONCLUSIONS

These results demonstrated the need for implements of sanitation programs in the sites for captive primates nurturing.

Reisolation and redescription of Balantidium duodeni Stein, 1867 (Litostomatea, Trichostomatia)

In this work, we present reisolation and redescription of Balantidium duodeni Stein, 1867 from the European common brown frog Rana temporaria Linnaeus, 1758 using light and electron microscopy. This species has a unique morphological feature--its cells are flattened along the dorsoventral axis. Because of its unique morphology and localization (duodenum) in the gastrointestinal tract of the host, it has been proposed to recognize B. duodeni as a member of separate genus, Balantidiopsis Penard, 1922. Molecular phylogenetic analysis demonstrates it to be close to the type species Balantidium entozoon (Ehrenberg, 1838). We argue that its placement into separate genus is not substantiated. We also propose to reinstate the genus Balantioides Alexeieff, 1931 with the type species Paramecium coli (Malmstein, 1857). The recently proposed generic name for this taxon, Neobalantidium Pomajbíková et al., 2013, is a junior synonym of the previously recognized name.

Balantidiosis: a rare accidental finding in the urine of a patient with acute renal failure

Balantidium coli is the only ciliated protozoan which is known to infect human and nonhuman primates. Route of infection is faecal-oral route. It is actively motile and causes mostly asymptomatic infections, or it may develop dysentery which is similar to that which is caused by Entamoeba histolytica. Here, we are describing a case of an accidental finding of B.coli in the urine of a patient who presented with acute renal failure, based on its characteristic morphology and motility which were seen on light microscopy. This is the third case of Urinary Balantidiosis which has been reported from India.

Assessment of gastrointestinal parasites in wild chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon

We tested 114 faecal samples from wild simian immunodeficiency virus (SIV)-positive (n = 43) and SIV-negative (n = 71) chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon for the presence of gastrointestinal parasites by direct smear. We observed cysts from different protozoa (Entamoeba coli and Entamoeba histolytica / Entamoeba dispar, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Balantidium coli and Blastocystis cells) and trophozoites from Troglodytella abrassarti and Balantidium coli. Eggs from different helminths (strongylids, Ascaris lumbricoides, Abbreviata caucasica, Trichuris sp., Capillaria sp., Enterobius anthropopeci, Bertiella sp., Hymenolepis diminuta and an undetermined fluke) were also observed. Finally, we observed eggs that could not be properly identified and classified. We did not observe any differences between the SIV+ and SIV- samples except for the unidentified eggs. The studied chimpanzees were highly parasitised by strongylid (85.1% of prevalence), Troglodytella (43.8%) and Blastocystis (2.9%), and the frequency of the other parasites ranged from 0.9 to 8.8%. These high levels of parasite infections could represent an additional burden in a population where there is a high rate of the SIV virus in circulation.

Balantidium Coli liver abscess: first case report from India

Protozoal infections are common in the tropics. Amoebic colitis is the commonest of these infections and can lead to liver abscess as a complication. Balantidium coli is a rare free moving protozoal parasite which is known to infest human large intestine causing a type of colitis very similar to that caused by Entamoeba histolytica. However this pathogen is not known to cause liver invasion in humans. We report here a case of liver abscess caused by B. coli, which is probably the first such case reported in Indian literature.

A rare case of urinary balantidiasis in an elderly renal failure patient

Balantidium coli is the largest ciliated protozoa infecting humans by the feco-oral transmission from pigs. Large gut is the most common site of involvement. Symptomatology varies from asymptomatic carrier to invasive dysentery. Extra-intestinal infections can occur in liver, lung and urogenital tract. There are very few case reports of urinary balantidiasis. We present a case of urinary balantidiasis in an elderly farmer having diabetes and chronic kidney disease. This case is reported for its rarity and future references.

Prevalence of Balantidium coli Infection in Bred Rhesus Monkeys (Macaca mulatta) in Guangxi, southern China

BACKGROUND

Balantidium coli infects humans, primates and pigs, causing serious diarrhea and dysentery. Little information on the prevalence of B. coli in primates is available in China. This investigation was conducted to determine the prevalence of B. coli infection in bred rhesus monkeys in Guangxi Zhuang Nationality Autonomous Region (GZNAR), southern China.

METHODS

A total of 120 fecal samples were collected from rhesus monkeys bred in cages in GZNAR and B. coli cysts and/or trophozoites were examined microscopically after sedimentation with water in May 2013.

RESULTS

(64.2%) samples were tested positive. The prevalence was 65% (39/60) and 63.3% (38/60) in female and male monkeys, respectively. 80% (48/60) cages in this nonhuman primate center were positive for B. coli.

CONCLUSION

The present survey revealed high circulation of B. coli in bred rhesus monkeys in GZNAR, which poses potential threats to animal and human health.

High prevalence of Strongyloides stercoralis infection among the elderly in Brazil

Little is known about the frequency of intestinal parasites in the elderly due to a lack of attention given to the occurrence of these infections among older adults. This study compares the frequency of Strongyloides stercoralis and other enteroparasites between elderly living in nursing homes (n = 100) and those noninstitutionalized (n = 100) from Uberlândia, state of Minas Gerais, southeastern Brazil, associated with data of epidemiological and socio-demographic conditions. Through coproparasitological examination of both groups, enteroparasites were detected in 15 of 200 individuals examined (7.5%; CI: 5.1- 9.9). S. stercoralis was the most frequent parasite 10/200 (5%; CI: 4.2-5.8), being significantly higher in males and in individuals with autonomy for daily living activities. There were no statistical differences in the prevalence of parasites between the two groups compared. In conclusion, S. stercoralis infection was highly prevalent in elderly patients and it does not depend on whether the individual was institutionalized or not.

[Intestinal parasitoses in Argentina: major causal agents found in the population and in the environment]

Intestinal parasitic diseases are widely spread in the world, with the highest prevalence in developing countries. Children are mainly affected, showing a decrease in physical and mental development, as well as the expected manifestations of the disease. This situation can be greatly enhanced in children with poor nutritional status. The World Health Organization considers intestinal parasitic diseases a major cause of morbidity, closely linked to poverty and poor personal hygiene, inappropriate handling of raw food, lack of sanitation, lack of potable water supply, and environmental fecal contamination. Some parasitic diseases are cosmopolitan while others have variable geographic distribution, due to different factors such as the presence of exclusive intermediate hosts. In the past few years, globalization allowed the spread of certain parasites from endemic to non-endemic regions. Even though people's customs influence on the frequency of certain parasites, environmental conditions are a determinant factor for parasite survival. In our country, due to the variety of soils and climatic conditions, several causative agents of these parasitoses can be found. The aim of this work was to review the literature on the intestinal parasitic agents found in Argentina in human fecal samples and its environment, as parasitic contamination constitutes a direct indicator of the infection risk by intestinal parasites.

Preliminary insights into the impact of dietary starch on the ciliate, Neobalantidium coli, in captive chimpanzees

Infections caused by the intestinal ciliate Neobalantidium coli are asymptomatic in most hosts. In humans and captive African great apes clinical infections occasionally occur, manifested mainly by dysentery; however, factors responsible for development of clinical balantidiasis have not been fully clarified. We studied the effect of dietary starch on the intensities of infection by N. coli in two groups of captive chimpanzees. Adult chimpanzees infected by N. coli from the Hodonín Zoo and from the Brno Zoo, Czech Republic, were fed with a high starch diet (HSD) (average 14.7% of starch) for 14 days, followed by a five-day transition period and subsequently with a period of low starch diet (LoSD) (average 0.1% of starch) for another 14 days. We collected fecal samples during the last seven days of HSD and LoSD and fixed them in 10% formalin. We quantified trophozoites of N. coli using the FLOTAC method. The numbers of N. coli trophozoites were higher during the HSD (mean ± SD: 49.0±134.7) than during the LoSD (3.5±6.8). A generalized linear mixed-effects model revealed significantly lower numbers of the N. coli trophozoites in the feces during the LoSD period in comparison to the HSD period (treatment contrast LoSD vs. HSD: 2.7±0.06 (SE), z = 47.7; p<<0.001). We conclude that our data provide a first indication that starch-rich diet might be responsible for high intensities of infection of N. coli in captive individuals and might predispose them for clinically manifested balantidiasis. We discuss the potential nutritional modifications to host diets that can be implemented in part to control N. coli infections.

Detection of intestinal protozoa in the clinical laboratory

Despite recent advances in diagnostic technology, microscopic examination of stool specimens remains central to the diagnosis of most pathogenic intestinal protozoa. Microscopy is, however, labor-intensive and requires a skilled technologist. New, highly sensitive diagnostic methods have been developed for protozoa endemic to developed countries, including Giardia lamblia (syn. G. intestinalis/G. duodenalis) and Cryptosporidium spp., using technologies that, if expanded, could effectively complement or even replace microscopic approaches. To date, the scope of such novel technologies is limited and may not include common protozoa such as Dientamoeba fragilis, Entamoeba histolytica, or Cyclospora cayetanensis. This minireview describes canonical approaches for the detection of pathogenic intestinal protozoa, while highlighting recent developments and FDA-approved tools for clinical diagnosis of common intestinal protozoa.

Emerging protozoal pathogens in India: How prepared are we to face the threat?

Emerging protozoal pathogens have become a major threat to human health. The number of protozoal pathogens causing human disease has been on the rise since the last two to three decades. Significant increase in the number of immunocompromised people, increase in international travel, deforestation, and widespread urban dwellings are some of the factors contributing to this changing epidemiology of protozoal diseases. Apart from Naegleria and Acanthamoeba, other free-living amoebae like Balamuthia and Sappinia are being reported to cause meningoencephalitis in humans. Plasmodium knowlesi, a zoonotic malarial parasite, has become a major cause of human malaria in Southeast Asia. Trypanosoma evansi and Trypanosoma lewisi, which normally infect horses and rodents respectively, have been reported to cause human trypanosomiasis in India. Balantidium coli is emerging as an important cause of dysentery especially in the immunocompromised population. In India, where a significant proportion of population lives in close proximity to cattle and pigs, B. coli can emerge as a significant pathogen in cases of dysentery, especially in the immunocompromised population. Babesia microti has become an important cause of transfusion transmitted babesiosis (TTB) in countries like the United States. As Babesia can be misdiagnosed as Plasmodium and blood transfusion is becoming common in India, it is necessary to develop diagnostic tests to rule out this pathogen in blood donors. Increased awareness among clinicians, pathologists, and microbiologists along with other factors like constant surveillance, improved diagnostic tests, and a high index of suspicion are important to detect and properly treat such emerging protozoal pathogens in humans.

Novel insights into the genetic diversity of Balantidium and Balantidium-like cyst-forming ciliates

Balantidiasis is considered a neglected zoonotic disease with pigs serving as reservoir hosts. However, Balantidium coli has been recorded in many other mammalian species, including primates. Here, we evaluated the genetic diversity of B. coli in non-human primates using two gene markers (SSrDNA and ITS1-5.8SDNA-ITS2). We analyzed 49 isolates of ciliates from fecal samples originating from 11 species of captive and wild primates, domestic pigs and wild boar. The phylogenetic trees were computed using Bayesian inference and Maximum likelihood. Balantidium entozoon from edible frog and Buxtonella sulcata from cattle were included in the analyses as the closest relatives of B. coli, as well as reference sequences of vestibuliferids. The SSrDNA tree showed the same phylogenetic diversification of B. coli at genus level as the tree constructed based on the ITS region. Based on the polymorphism of SSrDNA sequences, the type species of the genus, namely B. entozoon, appeared to be phylogenetically distinct from B. coli. Thus, we propose a new genus Neobalantidium for the homeothermic clade. Moreover, several isolates from both captive and wild primates (excluding great apes) clustered with B. sulcata with high support, suggesting the existence of a new species within this genus. The cysts of Buxtonella and Neobalantidium are morphologically indistinguishable and the presence of Buxtonella-like ciliates in primates opens the question about possible occurrence of these pathogens in humans.

Balantidium coli: an unrecognized cause of vertebral osteomyelitis and myelopathy

Balantidium coli is a ciliated protozoan parasite that primarily infects primates and pigs. It is the largest protozoan to infect humans and is a well-known cause of diarrhea and dysentery. Extraintestinal disease is uncommon, and extraintestinal spread to the peritoneal cavity, appendix, genitourinary tract, and lung has rarely been reported. The authors describe a case of vertebral osteomyelitis with secondary cervical cord compression caused by B. coli. The patient was a 60-year-old immunocompetent man presenting with quadriplegia of short duration. Magnetic resonance imaging of the cervical spine showed extradural and prevertebral abscess at the C3–4 level. Drainage of the abscess, C3–4 discectomy, and iliac bone grafting were performed. Histologically B. coli was confirmed in an abscess sample. To the best of the authors' knowledge, involvement of bone by B. coli has never been reported, and this case is the first documented instance of cervical cord compression due to B. coli osteomyelitis of the spine in the literature.

Neglected tropical diseases of Oceania: review of their prevalence, distribution, and opportunities for control

Among Oceania's population of 35 million people, the greatest number living in poverty currently live in Papua New Guinea (PNG), Fiji, Vanuatu, and the Solomon Islands. These impoverished populations are at high risk for selected NTDs, including Necator americanus hookworm infection, strongyloidiasis, lymphatic filariasis (LF), balantidiasis, yaws, trachoma, leprosy, and scabies, in addition to outbreaks of dengue and other arboviral infections including Japanese encephalitis virus infection. PNG stands out for having the largest number of cases and highest prevalence for most of these NTDs. However, Australia's Aboriginal population also suffers from a range of significant NTDs. Through the Pacific Programme to Eliminate Lymphatic Filariasis, enormous strides have been made in eliminating LF in Oceania through programs of mass drug administration (MDA), although LF remains widespread in PNG. There are opportunities to scale up MDA for PNG's major NTDs, which could be accomplished through an integrated package that combines albendazole, ivermectin, diethylcarbamazine, and azithromycin, in a program of national control. Australia's Aboriginal population may benefit from appropriately integrated MDA into primary health care systems. Several emerging viral NTDs remain important threats to the region.

Persistent digestive disorders in the tropics: causative infectious pathogens and reference diagnostic tests

BACKGROUND

Persistent digestive disorders account for considerable disease burden in the tropics. Despite advances in understanding acute gastrointestinal infections, important issues concerning epidemiology, diagnosis, treatment and control of most persistent digestive symptomatologies remain to be elucidated. Helminths and intestinal protozoa are considered to play major roles, but the full extent of the aetiologic spectrum is still unclear. We provide an overview of pathogens causing digestive disorders in the tropics and evaluate available reference tests.

METHODS

We searched the literature to identify pathogens that might give rise to persistent diarrhoea, chronic abdominal pain and/or blood in the stool. We reviewed existing laboratory diagnostic methods for each pathogen and stratified them by (i) microscopy; (ii) culture techniques; (iii) immunological tests; and (iv) molecular methods. Pathogen-specific reference tests providing highest diagnostic accuracy are described in greater detail.

RESULTS

Over 30 pathogens may cause persistent digestive disorders. Bacteria, viruses and parasites are important aetiologic agents of acute and long-lasting symptomatologies. An integrated approach, consisting of stool culture, microscopy and/or specific immunological techniques for toxin, antigen and antibody detection, is required for accurate diagnosis of bacteria and parasites. Molecular techniques are essential for sensitive diagnosis of many viruses, bacteria and intestinal protozoa, and are increasingly utilised as adjuncts for helminth identification.

CONCLUSIONS

Diagnosis of the broad spectrum of intestinal pathogens is often cumbersome. There is a need for rapid diagnostic tests that are simple and affordable for resource-constrained settings, so that the management of patients suffering from persistent digestive disorders can be improved.

Treatment of diarrhoea in rural African communities: an overview of measures to maximise the medicinal potentials of indigenous plants

Diarrhoea is a major cause of morbidity and mortality in rural communities in Africa, particularly in children under the age of five. This calls for the development of cost effective alternative strategies such as the use of herbal drugs in the treatment of diarrhoea in these communities. Expenses associated with the use of orthodox medicines have generated renewed interest and reliance on indigenous medicinal plants in the treatment and management of diarrhoeal infections in rural communities. The properties of many phenolic constituents of medicinal plants such as their ability to inhibit enteropooling and delay gastrointestinal transit are very useful in the control of diarrhoea, but problems such as scarcity of valuable medicinal plants, lack of standardization of methods of preparation, poor storage conditions and incertitude in some traditional health practitioners are issues that affect the efficacy and the practice of traditional medicine in rural African communities. This review appraises the current strategies used in the treatment of diarrhoea according to the Western orthodox and indigenous African health-care systems and points out major areas that could be targeted by health-promotion efforts as a means to improve management and alleviate suffering associated with diarrhoea in rural areas of the developing world. Community education and research with indigenous knowledge holders on ways to maximise the medicinal potentials in indigenous plants could improve diarrhoea management in African rural communities.

Balantidium coli in urine sediment: report of a rare case presenting with hematuria

Balantidium coli (B. coli) is the only trophic ciliate of low virulence causing dysentery in human. However, may be due to their active motility and invasive nature, they have been rarely described to cause infection in extraintestinal sites also. We herein describe a case where trophozoites of B. coli were detected in urinary sediment examination of an elderly female presenting with mild fever, dysuria and hematuria for last 1 week. The parasites were identified by their characteristic morphology and rapid spiraling motility. This is only the third case described in literature to detect B. coli in urine sediment.

Enteric protozoa in the developed world: a public health perspective

Several enteric protozoa cause severe morbidity and mortality in both humans and animals worldwide. In developed settings, enteric protozoa are often ignored as a cause of diarrheal illness due to better hygiene conditions, and as such, very little effort is used toward laboratory diagnosis. Although these protozoa contribute to the high burden of infectious diseases, estimates of their true prevalence are sometimes affected by the lack of sensitive diagnostic techniques to detect them in clinical and environmental specimens. Despite recent advances in the epidemiology, molecular biology, and treatment of protozoan illnesses, gaps in knowledge still exist, requiring further research. There is evidence that climate-related changes will contribute to their burden due to displacement of ecosystems and human and animal populations, increases in atmospheric temperature, flooding and other environmental conditions suitable for transmission, and the need for the reuse of alternative water sources to meet growing population needs. This review discusses the common enteric protozoa from a public health perspective, highlighting their epidemiology, modes of transmission, prevention, and control. It also discusses the potential impact of climate changes on their epidemiology and the issues surrounding waterborne transmission and suggests a multidisciplinary approach to their prevention and control.

Biopsy interpretation of colonic biopsies when inflammatory bowel disease is excluded

The interpretation of colonic biopsies related to inflammatory conditions can be challenging because the colorectal mucosa has a limited repertoire of morphologic responses to various injurious agents. Only few processes have specific diagnostic features, and many of the various histological patterns reflect severity and duration of the disease. Importantly the correlation with endoscopic and clinical information is often cardinal to arrive at a specific diagnosis in many cases.

A survey of gastrointestinal parasites of olive baboons (Papio anubis) in human settlement areas of Mole National Park, Ghana

Fecal samples from 55 free-ranging olive baboons (Papio anubis) in Mole National Park, Ghana, were collected 22 June-7 July 2008 and analyzed for gastrointestinal parasites. This is the first survey of baboon gastrointestinal parasites in Ghana and provides baseline data for this area. Ninety-three percent of samples were infected, leaving 7% with no parasites observed. Of those infected, there was a 76% prevalence of strongyles, 53% Strongyloides spp., 11% Abbreviata caucasica , 62% prevalence of Balantidium coli (trophozoites and cysts identified), 4% Entomeba hystolytica/dispar, and 47% unidentified protozoan parasites. Of the strongyle infections, 9% were identified as Oesophagostamum sp. One sample contained an unidentified spirurid nematode that resembled Gongylonema sp. Mole has a mixed forest-savanna habitat, and baboons frequently range into human areas, which makes them subject to parasites from each habitat and multiple sources of exposure. We found a high prevalence of nematode parasites, consistent with a wet or cooler forest environment, or high rates of fecal contamination. The presence of Strongyloides sp., E. hystolitica/dispar, and B. coli suggest potential public health risk from baboons, but molecular identification of these parasites, and documentation of their presence in local human populations, would be necessary to confirm zoonotic transmission.

Zoonotic enteric protozoa

A growing number of enteric protozoan species are considered to have zoonotic potential. Their clinical impact varies and in many cases is poorly defined. Similarly, the epidemiology of infections, particularly the role of non-human hosts, requires further study. In this review, new information on the life cycles and transmission of Giardia, Cryptosporidium, Entamoeba, Blastocystis and Balantidium are examined in the context of zoonotic potential, as well as polyparasitism and clinical significance.

Microbial eukaryotes in the human microbiome: ecology, evolution, and future directions

High throughput sequencing technology has opened a window into the vast communities of bacteria that live on and in humans, demonstrating tremendous variability, and that they play a large role in health and disease. The eukaryotic component of the human gut microbiome remains relatively unexplored with these methods, but turning these tools toward microbial eukaryotes in the gut will likely yield myriad insights into disease as well as the ecological and evolutionary principles that govern the gut microbiota. Microbial eukaryotes are common inhabitants of the human gut worldwide and parasitic taxa are a major source of morbidity and mortality, especially in developing countries, though there are also taxa that cause no harm or are beneficial. While the role microbial eukaryotes play in healthy individuals is much less clear, there are likely many complex interactions between the bacterial, archaeal, and eukaryotic microbiota that influence human health. Integrating eukaryotic microbes into a broad view of microbiome function requires an integrated ecological approach rather than one focused on specific, disease-causing taxa. Moving forward, we expect broad surveys of the eukaryotic microbiota and associated bacteria from geographically and socioeconomically diverse populations to paint a more complete picture of the human gut microbiome in health and disease.

Microbial eukaryotes in the human microbiome: ecology, evolution, and future directions

High throughput sequencing technology has opened a window into the vast communities of bacteria that live on and in humans, demonstrating tremendous variability, and that they play a large role in health and disease. The eukaryotic component of the human gut microbiome remains relatively unexplored with these methods, but turning these tools toward microbial eukaryotes in the gut will likely yield myriad insights into disease as well as the ecological and evolutionary principles that govern the gut microbiota. Microbial eukaryotes are common inhabitants of the human gut worldwide and parasitic taxa are a major source of morbidity and mortality, especially in developing countries, though there are also taxa that cause no harm or are beneficial. While the role microbial eukaryotes play in healthy individuals is much less clear, there are likely many complex interactions between the bacterial, archaeal, and eukaryotic microbiota that influence human health. Integrating eukaryotic microbes into a broad view of microbiome function requires an integrated ecological approach rather than one focused on specific, disease-causing taxa. Moving forward, we expect broad surveys of the eukaryotic microbiota and associated bacteria from geographically and socioeconomically diverse populations to paint a more complete picture of the human gut microbiome in health and disease.