Green synthesis of silver and iron oxide nanoparticles mediated photothermal effects on Blastocystis hominis

The evolution of parasite resistance to antiparasitic agents has become a serious health issue indicating a critical and pressing need to develop new therapeutics that can conquer drug resistance. Nanoparticles are novel, promising emerging drug carriers that have demonstrated efficiency in treating many parasitic diseases. Lately, attention has been drawn to a broad-spectrum nanoparticle capable of converting absorbed light into heat via the photothermal effect phenomenon. The present study is the first to assess the effect of silver nanoparticles (Ag NPs) and iron oxide nanoparticles (Fe3O4 NPs) as sole agents and with the combined action of the light-emitting diode (LED) on Blastocystis hominins (B. hominis) in vitro. Initially, the aqueous synthesized nanoparticles were characterized by UV-Vis spectroscopy, zeta potential, and transmission electron microscopy (TEM). The anti-blastocyst efficiency of these NPs was tested separately in dark conditions. As these NPs have a wide absorption spectrum in the visible regions, they were also excited by a continuous wave LED of wavelength band (400-700 nm) to test the photothermal effect. The sensitivity of B. hominis cysts was evaluated using scanning laser confocal microscopy whereas the live and dead cells were accurately segmented based on superpixels and the k-mean clustering algorithm. Our findings showed that this excitation led to hyperthermia that induced a significant reduction in the number of cysts treated with photothermally active NPs. The results of this study elucidate the potential role of photothermally active NPs as an effective anti-blastocystis agent. By using this approach, new therapeutic antiparasitic agents can be developed.

Frequency of Intestinal Parasites in Substance Abusers

OBJECTIVE

This study was conducted to investigate the frequency of intestinal parasites in substance abusers and to reveal its significance.

METHODS

The study was conducted in Van Yüzüncü Yıl University Medical Faculty Parasitology Research Laboratory and University of Health Sciences Turkey Van Training and Research Hospital between May 2019 and February 2020. The patient group included 150 patients with substance abuse who applied to the Alcohol and Drug Addicted Treatment Center of University of Health Sciences Turkey Van Training and Research Hospital, while the control group included 75 patients who had no chronic illness and did not use cigarettes, alcohol, or drugs. Stool samples were examined using native-Lugol and modified acid-fast staining methods.

RESULTS

In this study, one or more intestinal parasites were found in 21.3% of 150 patients who applied to the internal medicine outpatient clinic and had no chronic illness and did not use cigarettes, alcohol, or drugs. There was a statistically significant difference between the two groups in terms of the parasite frequency (p=0.03). In the patient group, Giardia intestinalis was detected in 7.3% (p=0.02), Blastocystis hominis in 6.7%, and Hymenolepis nana in 0.7%. Considering the frequency of parasites in terms of age groups, intestinal parasites were found at a higher rate in the 35 and younger age group (23.8%) than in the 36 and older age group (17.2%). Intestinal parasite positivity was found at the highest rate (23.8%) in those using methamphetamine. Constipation (79.3%) was the most prevalent in parasite-positive substance abusers, followed by diarrhea (23%).

CONCLUSION

This study contributed to the literature by determining the frequency of intestinal parasites in people addicted to substance, and it was revealed that intestinal parasite infections are a negative consequence of substance addiction. Conclusively, our findings revealed that intestinal parasites should be considered in substance abusers. Also, more detailed studies involving more individuals should be conducted to obtain information about intestinal parasite infections.

[Epidemiological Survey on Human Intestinal Protozoa in Xinjiang Uygur Autonomous Region in 2015]

OBJECTIVE

An epidemiological survey was made on human intestinal protozoa in Xinjiang Uygur Autonomous Region (Xinjiang) to evaluate recent control achievements and provide basis for making specific control strategies.

METHODS

Regions in Xinjiang were categorized by types of ecological system and geographical characteristics into five ecological areas（types I-V） according to the National Ecological Function Stratification issued by the Ministry of Environment Protection and Chinese Academy of Science and Technology. Stratification sampling was made in each ecological area. Feces from human of all ages were collected for morphological identification of protozoan species using the Iodine Liquid Direct Smear Method.

RESULTS

In the five ecological areas, 26 886 people from 132 survey sites in 39 counties (cities) were examined, with an examination rate of 81.47% （26 886/33 000）. The infection rate was 0.32%（85/26 886）. Four species of intestinal protozoa were detected, i.e., Entamoeba histolytica, Giardia lamblia, Blastocystis hominis, and Entamoeba coli, with an infection rate of 0.22% （60/26 886）, 0.03% （9/26 886）, 0.01% （2/26 886） and 0.61% （17/26 886）, respectively. Of the five areas, the type IV area had the highest infection rate of 0.75%（28/3 758）（P<0.05）. Besides, the infection rate was higher in males （0.24%, 33/13 623） than that in females （0.39%, 52/13 263） （P<0.05）, higher in age ranges of 21-30（1.40%, 16/3 959） and 31-40 years（0.46%, 22/4 799） than other age groups （P>0.05）, higher in housewives （0.48%, 2/418） than those with other occupations, higher in the Hui group （0.61%, 15/2 445） than that in other ethnic groups, as well as highest in populations with a primary education level （0.37%, 35/9 375） and lowest in those with a college level or above（0.20%, 8/3 945）.

CONCLUSION

The human intestinal protozoa infection was at a low level in Xinjiang in 2015.

[Analysis on parasitic infection of clinical samples from hospitals in Shanghai during 2011-2013]

OBJECTIVE

To analyze the results of parasitic pathogen detection on clinical samples from Shanghai hospitals during 2011-2013.

METHODS

Samples of serum, stool, sputum, body fluid and biopsy were collected from hospitals. The etiological, serological and molecular biology methods were used to detect parasitic infection cases.

RESULTS

During 2011-2013, a total of 16,151 clinical samples were collected. 855 parasitic infection were found from 5939 samples by pathogen detection, belonging to 32 species, with a detection rate of 14.4%. The positive rate of Blastocystis hominis and Entamoeba histolytica was 8.3% (494/5939) and 3.1% (186/5939), respectively. The rate of intestinal protozoa infection in under 20-year-old age group was higher than other age groups (P<0.05). No significant difference was found between males and females (P>0.05). Totally 10,212 serum samples were examined, the total antibody-positive rate was 7.1% (730/10,212). In the 730 positive samples, 173 (23.7%), 143 (19.6%), 139 (19.0%), 132 (18.1%), and 128 (17.5%) showed positive for the antibodies against Cysticercus cellulosae, Schistosoma japonicum, Paragonimus westermani, Toxoplasma gondii and Sparganum mansoni, respectively. The main source regions of protozoal infection were Shanghai (269 cases), Jiangsu (142 cases), Anhui (106 cases) and Zhejiang (82 cases). 89 cases were worm infection, the main source were Zhejiang (24 cases), Shanghai (18 cases), Jiangxi (11 cases).

CONCLUSION

Among the samples from hospitals, the major intestinal protozoans are Blastocystis hominis and Entamoeba histolytica, and the sero-positive cases are mainly Cysticercus cellulosae and Schistosoma japonicum infection.

[Investigation on the infection of Blastocystis hominis in populations in Bama Yao Autonomous County of Guangxi]

497 fecal specimens were collected from 5 randomly selected villages of Bama County in December 2011, and tested for Blastocystis hominis infection using improved centrifugal sedimentation with hydrochloric acid-ether. Data were analyzed by villages, gender, occupation, age groups and ethnic populations. The results showed that 215 people of 497 were positive, with a prevalence of 43.3% (215/497). Pandang village had the highest infection rate of 55.7% (68/122), significantly higher than the other villages (P<0.05). There was no significant difference in genders, occupations, age groups and ethnic populations (P>0.05).

Outbreak of gastrointestinal illness during Operation New Horizons in Pisco, Peru, July 2012

In July 2012, the U.S. Naval Medical Research Unit No. 6 investigated an outbreak of gastrointestinal illness characterized by diarrhea among U.S. service members participating in Operation New Horizons in Pisco, Peru. Overall, there were 25 cases of self-reported diarrheal illness among 101 respondents to a questionnaire (attack rate: 24.8%). Personnel who consumed food that was prepared at the two hotels where they were lodged were more likely to report diarrhea than those who did not eat at the hotels (40.9% [9/22] versus 20.3% [16/79]; RR=2.1; p=.047). The difference in diarrhea attack rates between lodgers at the two hotels was not statistically significant. Known or putative pathogens were identified in 72.7 percent (8/11) of samples tested: Blastocystis hominis, Shigella sonnei, diffusely adherent Escherichia coli, and norovirus genotypes I and II. The investigation's findings suggested a food-borne etiology from hotel kitchens. Among all personnel, hand-washing hygiene was reinforced; however, food sources were not restricted.

[Clinical and epidemiological characteristics of blastocystis hominis]

BACKGROUND

Blastocystis hominis is an intestinal parasite known since long. It is cosmopolitan and lives in the colon. It is still the subject of controversy regarding its pathogenicity and possibly opportunistic character.

AIM

We exhibit in this article the results obtained for 4 years on the epidemiological, clinical and biological character and opportunistic Blastocystis hominis, often overlooked in the examination of parasitological laboratories city.

METHODS

This is a retrospective study of 3257 stool examination (PSE), performed in the Mycology Laboratory of Parasitology of the Charles Nicolle Hospital in Tunis over a period of 4 years (January 2005-December 2008). Detection of Blastocystis hominis has been made by microscopic examination of samples by direct examination and concentration.

RESULTS

Blastocystis was found in 7.27% of cases and 48.5% in men. Endolimax nanus is the parasite most frequently associated with Blastocystis (40.4% of cases). The port was symptomatic in 72.1% of cases, diarrhea is the symptom most often found (27.7%). There is a seasonal distribution; in fact, it is more frequently diagnosed in summer and autumn.

CONCLUSION

The absence of gravity and the saprophytic nature of this infection do not lead to an indication for treatment even among profoundly immunosuppressed individuals. Only the persistence of clinical disorders associated with the detection of the parasite and in the absence of other micro-organisms and intestinal parasites justifies the treatement. Metronidazole is the molecule used conventionally.

Epidemiology of Blastocystis hominis and other intestinal parasites among the immigrant population in northeastern Taiwan by routine physical examination for residence approval

BACKGROUND AND PURPOSE

Blastocystis hominis has not been reported as an endemic disease in Taiwan, but high prevalence rates have been found among immigrants. Due to the increasing number of immigrants in Taiwan, B. hominis may become a public health problem in Taiwan. This study was performed to determine the prevalence of B. hominis among immigrant populations.

METHODS

Stool examination data from the Immigrant Physical Examination for Residence Approval in 2006 were examined.

RESULTS

Among the 932 immigrants from 4 countries, 188 individuals (20.2%) were infected with B. hominis. The prevalence was higher among immigrants from Southeast Asian countries (Indonesia, 26.4%; Vietnam, 20.6%; The Philippines, 19.3%) than among those from China (7.6%). Coinfection with intestinal parasites of fecal-oral transmission (Endolimax nana and Entamoeba hartmannii) was a risk factor for B. hominis infection (odds ratio, 16.9; 95% confidence interval, 6.84-43.55). No significant differences in prevalence for sex and age were observed.

CONCLUSION

To prevent local transmission and endemic spread of B. hominis, obligatory routine health screening for immigrant populations and early eradication of the infection are important policies for this high-risk group.

Absence of an Association Between Enteric Parasites in the Manifestations and Pathogenesis of HIV Enteropathy in Gay Men

49 gay men confirmed to be infected with the human immunodeficiency virus (HIV) and 9 HIV seronegative gay men participated in a pilot study comparing clinical status and enteric parasite load with gastrointestinal structure, function and symptomatology. Cases included 16/49 (33%) men who were CDC stage II, 7/49 (14%) who were CDC stage III, and 26/49 (53%) who were CDC stage IV. The mean CD4-lymphocyte count was 476 +/- 199 (SD)/microliter. The prevalence of enteric parasitic flora was similar in HIV seropositive patients and controls. Seven cases had enteric infection with pathogenic agents including 3 patients with Entamoeba histolytica, and 4 patients with Giardia lamblia, one of whom also had cryptosporidiosis. Other cases were most frequently colonized with Blastocystis hominis (44%) and Endolimax nana (41%) regardless of the HIV clinical status. HIV seropositive patients with enteric parasitic colonization tended to have lower mean levels of serum IgA than cases without parasites. Duodenal morphometric mucosal changes demonstrated a significant decrease in the mean villous height (p < 0.01) with no elongation of the crypt depth in HIV-infected patients with and without diarrhea compared to controls. Despite gastrointestinal symptoms including diarrhea and weight loss being more prevalent in HIV infected individuals than controls, no correlations were found between the presence of particular enteric parasites, gastrointestinal symptomatology, the clinical HIV status of the CD4-lymphocyte count, the malabsorption of D-xylose or morphometric changes in the duodenum.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chronic angioedema and blastocystis hominis infection]

The presence of urticaria associated with Blastocystic Hominis infection has been described in very few studies. To the best of our knowledge, no cases of chronic angioedema associated with Blastocystic hominis have been published. The clinical and immunological data of a patient with said association is presented. In the last 5 years, a 21 year old woman suffered episodic spells of angioedema which affected her lips, face and upper limbs accompanied by recurring urticaria. The patient continually used antihistamines and corticoids. Laboratory and immunological tests were normal. Blastocystic hominis in faeces was identified on three occasions. The angioedema and urticaria, as well as the intestinal infection, were successfully treated with paramomycin sulphate. The angiodema and urticaria continue in remission after 24 months of followup care. This case helps to encourage studies to establish an association between the infection by Blastocystis hominis and the presence of chronic angioedema which does not respond to standard treatment, as this condition can seriously affect the quality of life of sufferers.

Frequency of Giardia lamblia among children in Dohuk, northern Iraq

Out of 1261 stool specimens collected from children in Dohuk city, northern Iraq, the prevalence of Giardia lamblia infection was 38.5%. The highest rate of infection was in orphan care centres (48.1%) and the lowest in the paediatric hospital (31.3%). The age group 10-12 years had the highest rate (81.2%) and 7-9 years the lowest (22.9%); boys had a higher rate than girls. Some infected samples (70/486) showed double or triple infections and G. lamblia was combined with Hymenolepis nana, Blastocystis hominis, Entamoeba histolytica and Iodamoeba buetschlii.

Blastocystis hominis--an emerging and imitating cause of acute abdomen in children

Two children aged 12 and 11 years with a similar history of abdominal pain, nausea, vomiting and fever with abdominal tenderness, and muscle guarding at the right lower quadrant for few days were admitted to our hospital. They subsequently developed diarrhea but without clinical relief. Just before the decision of laparotomy, both patients were diagnosed as having Blastocystis hominis infection with light microscopic examination of the stools and were treated uneventfully with the appropriate antibiotics.

[Blastocystosis or Zierdt-Garavelli disease: a clinical pathway]

The author presents the clinical pathway of blastocystosis, a disease due to Blastocystis hominis, an intestinal parasite that has long been enigmatic, which can occasionally be the cause of clinical manifestations.

[Impact of blastocystis hominis infection on ultrastructure of intestinal mucosa in mice]

OBJECTIVE

To observe the ultrastructural change ot intestinal mucosa in mice infected with Blastocystis hominis, and to study the pathogenic mechanism of B. hominis infection.

METHODS

20 Kunming mice were randomly divided into 4 groups: group A treated with immunosuppressant (dexamethasone), group B without immunosuppressant, group C as normal control and group D as immunosuppressant control. Groups A and B were then orally infected with 20(4) cysts of B. hominis. Groups C and D were treated as control by infusing same volume of Locke's solution. Six days after inoculation, mice in each group were killed and mucosa of ileocecum was observed by transmission electron microscope (TEM) and scanning electron microscope (SEM).

RESULTS

Under SEM, B. hominis located in enteric cavity and on the surface of ileocecum mucosa. Individual parasites also invaded into mucosa and its fold. Partial destruction of microvilli on the mucosa was observed. TEM observation indicated a reduction of microvilli on the surface of absorptive cells. Mitochondrial edema, rough endoplasmic reticulum dilatation and degranulation were found on absorptive cells and goblet cells. Lymphocyte infiltration and eosinophilia were found in intercellular stroma. Pathological changes in group A were more serious than that of group B. No abnormal change on the mucosal ultrastructure was found in groups C and D.

CONCLUSIONS

B. hominis infection causes significant ultrastructural lesion on the ileocecal mucosa in mice. Immune status of the mice can affect the degree of the lesion due to infection.

Epidemiology of Blastocystis hominis and other intestinal parasites in a Vietnamese female immigrant population in southern Taiwan

There has been a rapid increase in cross-border female marriage immigrants in Taiwan. In this study, 1,434 Vietnamese female marriage immigrants arriving between July 1998 and June 2001 were examined for intestinal parasites. Most (77.9%) of these women were 20-29 years of age. The prevalence of intestinal parasite infection was 37.7%, and the trend increased from 1999 to 2001 (statistically significant, p < 0.0001), but decreased among age subgroups (p < 0.0001). Among the 20 species of intestinal parasites found in this study, 10 species (27.8%) were transmitted via the fecal-oral route, 5 (14.6%) via the soil-mediated route, and 5 (0.7%) by food-borne infection. The prevalence of blastocystosis (20.4%) and hookworm (9.7%) remained high among this population. The results provide unprecedented information on intestinal parasitic infection among these immigrants in southern Taiwan and recommend that appropriate health care be given after parasite infection is confirmed in these migrant communities.

Chronic urticaria due to Blastocystis hominis

A 24-year-old woman had a 9-week history of second to third daily urticaria that began after an episode of contact urticaria to topical bufexamac. She was found to have an underlying gastrointestinal infection with Blastocystis hominis. This was thought to be clinically relevant as she had a history of mild chronic diarrhoea. After treatment of the Blastocystis hominis, her urticaria ceased. This could indicate the importance of performing stool microscopy and culture on all patients with chronic urticaria of unknown aetiology. The relationship of urticaria to intestinal parasites and the possibility that non-steroidal anti-inflammatory medications could act as cofactors that help precipitate an urticarial reaction is discussed.

[Experimental infection of mice with Blastocystis hominis]

OBJECTIVE

To seek a better pathway and proper number of parasites for Blastocystis hominis (B.h) infection in normal and immunocompromised ICR mice.

METHODS

(1) 10(4), 10(5) and 10(6) B.h, cultured in RPMI 1640 medium from 3 generations were used to infect mice through oral and rectum; (2) 10(6) B.h were used to infect immunocompromised mice through rectum. The reproduction of B.h in gastrointestinal tract and the pathologic changes in the tissues were observed.

RESULTS

Mice were infected by B.h through either oral or rectum. The infected immunocompromised mice showed slow locomotion, depressed, lethargy, and descended body weight. Some infected mice discharged mucus feces, a few of them died during the experiment. Parasites were found in the whole gastrointestinal tract. Severe edema, hyperemia and congestion were observed in the tissues of jejunum, ileum, cecum and colon. The epithelia of small intestine and colonic mucous membrane showed exfoliation, inflammatory cell infiltration in submucosa, and structural changes in glands.

CONCLUSION

Mice were more susceptible to Blastocystis hominis infection through rectum than orally. The parasites can be found in the whole gastrointestinal tract of mice, and can breed rapidly and cause significant pathological change in the gastrointestinal mucosa in immunocompromised mice.

Effect of nitazoxanide in persistent diarrhea and enteritis associated with Blastocystis hominis

BACKGROUND & AIMS

The aim of this study was to evaluate the efficacy of nitazoxanide for the treatment of diarrhea and enteritis associated with Blastocystis hominis as the sole identified pathogen in children and adults from the Nile delta of Egypt.

METHODS

Two prospective, randomized, double-blind, placebo-controlled studies were conducted. Nitazoxanide 500 mg (as a 500-mg tablet) was administered twice daily for 3 days in patients aged 12 years or older, 200 mg (as 10 mL of an oral suspension) was administered twice daily for 3 days in patients aged 4-11 years, and 100 mg (as 5 mL of an oral suspension) was administered twice daily for 3 days in patients aged 1-3 years.

RESULTS

Four days after the completion of therapy, 36 (86%) of the 42 patients who received nitazoxanide showed resolution of symptoms compared with 16 (38%) of 42 patients who received placebo (P<.0001). Thirty-six (86%) of the 42 patients who received nitazoxanide were free of B hominis organisms in each of 3 posttreatment stool samples compared with only 5 (12%) of 42 patients who received placebo (P<.0001). Response rates in patients receiving the tablets and the suspension were identical.

CONCLUSIONS

These findings suggest that B hominis is pathogenic in some patients and can be treated effectively with nitazoxanide. Alternatively, the possibility that nitazoxanide is effective in treating other unidentified causes of persistent diarrhea and enteritis warrants further study.

No correlation between clinical symptoms and Blastocystis hominis in immunocompetent individuals

Abstract Background and Aim: Previous reports regarding the clinical significance and pathogenicity of Blastocystis hominis have been contradictory. The aim of this study was to examine the association between Blastocystis and gastrointestinal symptoms in immunocompetent individuals.

METHODS

We monitored over 2800 healthy people for a period of 15 months, and took stool specimens during both asymptomatic periods and during periods of gastrointestinal symptoms.

RESULTS

After exclusion of individuals who had simultaneous identification of other fecal pathogens, we compared the proportions of asymptomatic versus symptomatic individuals positive for Blastocystis and found no significant difference (P = 0.5). Symptom status did not correlate with parasite abundance. We found that some individuals were likely to have Blastocystis detected during both asymptomatic and symptomatic periods, possibly suggesting carriage of the organism.

CONCLUSION

In conclusion, we found no correlation between clinical symptoms and the presence or absence of Blastocystis among this healthy cohort.

Clinical characteristics and endoscopic findings associated with Blastocystis hominis in healthy adults

Ninety-nine individuals with stools positive for Blastocystis hominis but negative for other parasites were identified from medical records of healthy adults who had received a physical examination at Taipei Veterans General Hospital from November 2000 to October 2002. The medical records of these 99 positive cases and 193 randomly selected controls, matched for age, sex, and date of examination, were retrospectively reviewed. The pathogenicity of B. hominis could not be demonstrated due to a lack of association with the development of gastrointestinal symptoms or pathologic findings on endoscopic examination. Multivariate analyses revealed that chronic hepatitis B infection was a predisposing condition to the acquisition of B. hominis (odd ratio = 2.848, 95% confidence interval = 1.299-6.242, P = 0.009), and concentration of urate was significantly lower in B. hominis-positive individuals (mean +/- SD = 361.64 +/- 87.44 versus 392.57 +/- 93.38 micromol/L; P = 0.009). Among the 64 individuals who underwent gastric biopsy, Helicobacter pylori was found more frequently in the individuals harboring B. hominis (19 of 26 versus 15 of 38; P = 0.017).

Epidemiological survey of Blastocystis hominis in Huainan City, Anhui Province, China

AIM: To provide scientific evidence for prevention and controlling of blastocystosis, the infection of Blastocystis homonis and to study its clinical significance in Huainan City, Anhui Province, China.

METHODS: Blastocystis homonis in fresh stools taken from 100 infants, 100 pupils, 100 middle school students and 403 patients with diarrhea was smeared and detected with method of iodine staining and hematoxylin staining. After preliminary direct microscopy, the shape and size of Blastocystis homonis were observed with high power lens. The cellular immune function of the patients with blastocystosis was detected with biotin-streptavidin (BSA).

RESULTS: The positive rates of Blastocystis homonis in fresh stools taken from the infants, pupils, middle school students and the patients with diarrhea, were 1.0% (1/100), 1.0% (1/100), 0% (0/100) and 5.96% (24/403) respectively. Furthermore, the positive rates of Blastocystis homonis in the stool samples taken from the patients with mild diarrhea, intermediate diarrhea, severe diarrhea and obstinate diarrhea were 6.03% (14/232), 2.25% (2/89), 0% (0/17) and 12.31% (8/65) respectively. The positive rates of Blastocystis homonis in fresh stools of male and female patients with diarrhea were 7.52% (17/226) and 3.95% (7/177) respectively, and those of patients in urban and rural areas were 4.56% (11/241) and 8.02% (13/162) respectively. There was no significant difference between them (P > 0.05). The positive rates of CD₃⁺, CD₄⁺, CD₈⁺ in serum of Blastocystis homonis-positive and-negative individuals were 0.64 ± 0.06, 0.44 ± 0.06, 0.28 ± 0.04 and 0.60 ± 0.05, 0.40 ± 0.05 and 0.30 ± 0.05 respectively, and the ratio of CD₄⁺/CD₈⁺ of the two groups were 1.53 ± 0.34 and 1.27 ± 0.22. There was significant difference between the two groups (P < 0.05, P < 0.01).

CONCLUSION: The prevalence of Blastocystis hominis as an enteric pathogen in human seems not to be associated with gender and living environment, and that Blastocystis hominis is more common in stool samples of the patients with diarrhea, especially with chronic diarrhea or obstinate diarrhea. When patients with diarrhea infected by Blastocystis hominis, their cellular immune function decreases, which make it more difficult to be cured.

Prevalence of Blastocystis hominis carriage in Thai army personnel based in Chonburi, Thailand

Blastocystis hominis is one of the most common intestinal parasites found in humans. The prevalence of B. hominis carriage in personnel who worked in the First Army Support Command, Chonburi, Thailand, was determined. Forty-four percent of 616 stool samples were positive for B. hominis using both simple smear and concentration (Formalin/ethyl acetate) techniques. The usefulness of the concentration technique in the diagnosis of B. hominis has been confirmed. Of 272 positive specimens, 75% were detected by simple smear and 25% were additionally identified by the concentration technique. The prevalence of B. hominis carriage was highest among the privates who had lived longest in this command. This finding indicates that they might have acquired B. hominis during their stay at this base. The significantly high prevalence of B. hominis carriage was found in the Ordnance Ammunition Battalion. In this battalion, privates who had education lower than the secondary school level had significantly greater risk of B. hominis carriage.

Blastocystis hominis]

Ein 50-jähriger Künstler kehrt nach sechsjährigem Auslandaufenthalt in Hawaii in die Schweiz zurück. Seit einigen Wochen beklagt er breiigen Stuhlgang und Flatulenz bei normaler Stuhlfrequenz und sonst gutem Allgemeinbefinden. Bei unauffälligem Laborbefund wird in dreimaligen Stuhluntersuchungen jeweils Blastocystis hominis vorgefunden, ein Parasit dessen pathogene Dignität kontrovers diskutiert wird. Bereits nach einigen Dosen Metronidazol (500 mg) bessern sich die Blähungsgefühle und der Stuhl erhält seine normale Konsistenz zurück. Bei einem symtomatischen Patienten bei welchem Blastocystis hominis im Stuhl vorgefunden wird, sollte nur dann behandelt werden, wenn die aktive Suche nach dem Vorliegen eines weiteren Organismus negativ ausgefallen ist und andere Ursachen für das Beschwerdebild ausgeschlossen werden konnten.

Intestinal parasites, including Cryptosporidium species, in Iraqi patients with sickle-cell anaemia

Stool samples were obtained from individuals admitted to three hospitals in Basra during November 1997-May 1998. Of 40 patients with sickle-cell anaemia, 25 (62.5%) had parasitic infections. In the apparently healthy comparison group, 26 of 175 individuals (14.8%) had intestinal parasitic infections, a statistically significant difference. The most common intestinal parasites isolated in the sickle-cell patients were Blastocystis hominis (36%) and Giardia lamblia (28%). The isolation rate of Cryptosporidium species in sickle-cell patients (5%) was not significantly different from that in apparently healthy individuals (1.14%). We report for the first time the isolation of Isospora belli from a sickle-cell patient in Iraq and the Mediterranean region.

[Acute infectious lymphocytosis associated to Giardia lamblia and Blastocystis hominis coinfection]

Acute infectious lymphocytosis is characterized by marked peripheral blood lymphocytosis, often associated with a mild, nonspecific febrile illness. We present a 4-year-old girl with acute infectious lymphocytosis associated with Giardia lamblia and Blastocystis hominis coinfection. Analysis of peripheral lymphocyte markers showed overall proliferation of B and T cells with a reduction in the proportion of T cells, especially in the CD4T cell subpopulation. Hematologic values returned to normal after treatment with metronidazole.

Inhibition of enteric parasites by emulsified oil of oregano in vivo

Oil of Mediterranean oregano Oreganum vulgare was orally administered to 14 adult patients whose stools tested positive for enteric parasites, Blastocystis hominis, Entamoeba hartmanni and Endolimax nana. After 6 weeks of supplementation with 600 mg emulsified oil of oregano daily, there was complete disappearance of Entamoeba hartmanni (four cases), Endolimax nana (one case), and Blastocystis hominis in eight cases. Also, Blastocystis hominis scores declined in three additional cases. Gastrointestinal symptoms improved in seven of the 11 patients who had tested positive for Blastocystis hominis.

Intestinal protozoa in HIV-infected patients: effect of rifaximin in Cryptosporidium parvum and Blastocystis hominis infections

In HIV-1 infected patients severe enteritis and chronic diarrhea are often documented as a consequence of multiple opportunistic infections. We analyzed 48 HIV-1 positive patients for the presence of intestinal pathogenic protozoa. Patients with CD4 > or = 200/mm3 showed a higher prevalence of a single pathogenic protozoa than patients with CD4 < or =200/mm3, who showed the presence of multiple protozoal infections. Patients who proved positive for only a single protozoa, Cryptosporidium or Blastocystis, were also positive, by stool culture, for the presence of Proteus mirabilis (3 samples), Citrobacter freundii (3 samples), Escherichia coli (one sample) or Enterobacter cloacae (one sample). Treatment with rifaximin (600 mg, 3 times a day, for 14 days) was efficacious in resolving the clinical symptoms and clearing protozoan infections in HIV-1 infected patients with CD4 > or = 200/mm3, who presented enteric and systemic symptoms due to Criptosporidium or Blastocystis associated with enteropathogenic bacteria.

Irritable bowel syndrome in patients with Blastocystis hominis infection

The prevalence of Blastocystis hominis in stool specimens of individuals with gastrointestinal symptoms was evaluated to study a possible link between the protozoan and the irritable bowel syndrome. According to the Rome diagnostic criteria, 388 patients were evaluated. Altogether, 81 patients were classified as affected by irritable bowel syndrome. Blastocystis hominis was recovered from the stools of 38 subjects, 15 of whom belonged to the group with irritable bowel syndrome (P = 0.006). In addition, patients with irritable bowel syndrome were significantly more likely to have five or more Blastocystis hominis organisms per field (P = 0.031). In conclusion, there was a set of patients with irritable bowel syndrome in whom the presence of Blastocystis hominis may not be incidental.

Prevalence and clinical relevance of Blastocystis hominis in diverse patient cohorts

The pathogenicity of Blastocystis hominis is extensively debated in the medical literature. Therefore, we did a prevalence study to investigate the association between the presence of several intestinal parasites and gastrointestinal symptoms in diverse patient cohorts. The study population consisted of 1216 adults, including immunocompromised patients, institutionalized psychiatric or elder subjects, immigrants from developing countries, travellers to developing tropical countries and controls. Several variables for each risk group were considered. Stools specimens, collected in triplicate, were processed by the same technicians. Clinical data about each subject were provided by standardized questionnaires. The presence of gastrointestinal symptoms were related to the presence of any parasite. In addition, on the basis of microbiological results, five subgroups of subjects were evaluated. The results showed a high prevalence of parasites in all the risk groups. Immunocompromised status, recent arrival from developing countries and the presence of behavioural aberrations were significantly related to presence of parasites. B. hominis was the parasite most frequently detected in each studied group. B. hominis showed a significant correlation with gastrointestinal symptoms only when detected in the group including subjects with a severe immunodepression. Immunodepression seems to be a factor of primary importance of the pathogenic role of B. hominis.

Cytopathic effect of Blastocystis hominis after intramuscular inoculation into laboratory mice

The present study investigated the pathogenesis of Blastocystis hominis by intramuscular injection of the organism into experimental mice. A total of 27 naïve BALB/c mice aged 6-8 weeks were injected in the leg muscle with axenic culture isolate B of B. hominis. Histological examination at different times revealed that B. hominis could produce a severe inflammatory reaction and myonecrosis. Most changes were observed at 6 h after injection and for up to 2-3 days. By 2 weeks the muscle had regained normal histology. There was infiltration of polymorphonuclear leukocytes (PML) into the injection site, indicating that B. hominis had a strong chemoattractant activity for PML.

The role of Blastocystis hominis as a possible intestinal pathogen in travellers

The role of Blastocystis hominis as a pathogen for man has been controversially discussed, while travel history has been implicated as a risk factor of infection. Few controlled studies of the association between B. hominis and symptomatic diseases have been performed. Therefore, a case-control study among 795 German tourists returning from tropical countries was conducted. The prevalence of the organism among patients with and without symptoms was assessed. Blastocystis hominis was detected in 69 of 469 (14.7%) patients with diarrhoea and in 21 of 326 (5.7%) controls. However, other organisms causing diarrhoea were detected in 18 of the 69 (26.1%) symptomatic patients with B. hominis. Thus, 51 of 469 (10.8%) symptomatic patients had B. hominis in the absence of other pathogens in their stool, significantly more than in the asymptomatic group (5.2%; P = 0.005). Irrespective of the development of symptoms, the organism was most frequently acquired during journeys to the Indian subcontinent. The results of this study suggest that B. hominis is associated with development of diarrhoea in travellers to tropical destinations and that frequently concurrent infections with other organisms occur.

[Prevalence of Blastocystis hominis infection in schoolchildren from Bolivar City, Venezuela]

Blastocystis hominis is found in about 25% of feces in normal asymptomatic people. Its pathogenic role is still discussed. A prospective study was performed to determine the prevalence of B. hominis infection in schoolchildren from Bolivar City. We evaluated 446 children, between five and fourteen years old, both sexes, using direct examination of feces and Willis Method. They were also evaluated clinically. Results showed that B. hominis had a prevalence of 16.8%. We did not find a statistically significant association between sex (P > 0.05) or age and infection with B. hominis (x2 = 1.94 g.l = 4). In 39 schoolchildren (52.0%) we identified other parasites along with B. hominis, the most frequent was Trichuris trichiura as helminth and Giardia lamblia as protozoan. We observed B. hominis alone in 36 cases (48.0%). There was a spectrum of clinical symptoms in 41 (54.7%) of all children evaluated. Diarrhea was the most frequently clinical manifestation observed. Other studies are necessary to determine clinical relevance of B. hominis in school population in Bolivar City.