Genetic variation of NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequence in adult Necator americanus hookworms recovered from a female patient in Thailand.

Two female and one male adult hookworms were recovered from a female patient in Thailand. Based on gross and microscopic morphology, the three hookworms are members of Necator americanus. Phylogenetic reconstruction based on partial NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequences shows that these hookworms belong to the same genetic lineage as N. americanus adult worm from Zhejiang, China. The male and female hookworms were genetically distinct, belonging to two different nad1-haplotypes. This is the first report targeting the nad1 gene on the identification and genetic characterization of the human hookworms originated from infected patient. The nad1 gene marker is useful for species and higher taxa differentiation of hookworms.

Genetic variation of NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequence in adult Necator americanus hookworms recovered from a female patient in Thailand

@#Two female and one male adult hookworms were recovered from a female patient in Thailand. Based on gross and microscopic morphology, the three hookworms are members of Necator americanus. Phylogenetic reconstruction based on partial NADH dehydrogenase subunit 1 (nad1) mitochondrial gene sequences shows that these hookworms belong to the same genetic lineage as N. americanus adult worm from Zhejiang, China. The male and female hookworms were genetically distinct, belonging to two different nad1-haplotypes. This is the first report targeting the nad1 gene on the identification and genetic characterization of the human hookworms originated from infected patient. The nad1 gene marker is useful for species and higher taxa differentiation of hookworms.

Molecular identification of Gnathostoma spinigerum (Nematoda: Gnathostomatidae) as causative agent of human gnathostomiasis in Thailand.

A 43-year-old male residing in Prachin Buri Province, Thailand, was admitted to the Siriraj University Hospital of Mahidol University, Thailand, in July 2014 with right eyelid swelling and serpiginous lesion for three weeks. A nematode specimen was accidentally recovered from his upper right eyelid area. The body of the worm was cylindrical and measured 11.0 × 1.4 mm. The head bulb had eight circles of transverse spines. Anterior half of the body was covered with rows of comb-like pointed spines. The tail part was rounded dorsally and flattened ventrally and no copulatory spicule was observed at the posterior end. It was morphologically identified as an immature female worm of gnathostome species. Sequence analysis for partial cytochrome c oxidase subunit I (COI) gene revealed this recovered nematode as Gnathostoma spinigerum.

Genetic diversity of infective larvae of Gnathostoma spinigerum (Nematoda: Gnathostomatidae) in freshwater swamp eels from Thailand.

Human gnathostomiasis is a food-borne zoonosis caused by a tissue nematode of the genus Gnathostoma. The disease is highly endemic in Asia, including Thailand. The freshwater swamp eel (Monopterus albus), the second intermediate host of the gnathostome nematode, has an important role in transmitting the infection in Thailand. Surveys on the infective larvae of Gnathostoma spinigerum based on morphological features in freshwater swamp eels have been performed continuously and reported in Thailand. However, there is still limited molecular data on intra-species variations of the parasite. In this study, a total of 19 third-stage larvae of morphologically identified G. spinigerum were collected from 437 liver samples of freshwater swamp eels purchased from a large wholesale market in Bangkok, Thailand. Molecular characterization based on mitochondrial cytochrome c oxidase subunit I (COI) sequences was performed to elucidate their genetic variations and phylogenetic relationship. Among the 19 infective larvae recovered from these eels, 16 were sequenced successfully. Phylogenetic analyses inferred from the partial COI gene showed the presence of three distinct COI haplotypes. Our findings confirm the presence of G. spinigerum as the main species in Thailand.

Geographical distribution and incidence of Angiostrongylus lungworms (Nematoda: Angiostrongylidae) and their rodent hosts in Thailand.

The rat lungworm Angiostrongylus cantonensis, a zoonotic parasite, is known to be responsible for eosinophilic meningitis and meningoencephalitis in humans in many countries worldwide. Another congener A. malaysiensis is a potential pathogen. Rodents as natural definitive host of the parasites are abundant and globally widespread. In this study, the prevalence of Angiostrongylus infection in wild rats was investigated in twenty-four provinces of Thailand during the period December 2011 to June 2014. Of the 669 wild rats sampled, 46 (6.88%) were infected with Angiostrongylus lungworms. The rodents harbouring A. cantonensis worms included Bandicota indica, Bandicota savilei, Rattus exulans, Rattus norvegicus, Rattus rattus complex and Rattus tiomanicus, and those harbouring A. malaysiensis were B. savilei, Rattus losea, R. norvegicus and R. rattus complex. No parasite was recovered from Maxomys surifer (n=11), Mus musculus (n=1), Niviventer fulvescens (n=2), Rattus argentiventer (n=4), Rattus nitidus (n=3) and Sundamys muelleri (n=3). In positive rats, the incidence of infection with Angiostrongylus lungworms was variable among host species and provinces. There were also considerable variation in the proportion of male and female worms among rodent hosts and localities. Two hundred and thirty-five of the collected worms were male and 282 were female. The mean worm burden in the positive rats was 11.24 and ranged from 1 to 61. 81.82% (423/517) of the adult worms were morphologically identified as A. cantonensis, and 18.18% (94/517) were A malaysiensis. One R. rattus from Prachuap Khiri Khan had mixed infection of A. cantonensis and A. malaysiensis (10 worms of each species). The overall number of male (202) and female (221) A. cantonensis worms was not significantly different (χ2 = 0.86, 0.50 > P > 0.30). However, the overall number of male (33) and female (61) A. malaysiensis worms was significantly different (χ2 = 8.34, P < 0.01). The present study added one new definitive host (R. tiomanicus) for A. cantonensis and two new definitive hosts (B. savilei and R. losea) for A. malaysiensis in Thailand. Our data update and contribute significantly to existing knowledge of the geographical distribution of A. cantonensis in wild rats in Thailand and confirm the occurrence of A. malaysiensis throughout the country.

Geographical distribution and incidence of Angiostrongylus lungworms (Nematoda: Angiostrongylidae) and Geographical distribution and incidence of Angiostrongylus lungworms (Nematoda: Angiostrongylidae) and their rodent hosts in Thailand

The rat lungworm Angiostrongylus cantonensis, a zoonotic parasite, is known to be responsible for eosinophilic meningitis and meningoencephalitis in humans in many countries worldwide. Another congener A. malaysiensis is a potential pathogen. Rodents as natural definitive host of the parasites are abundant and globally widespread. In this study, the prevalence of Angiostrongylus infection in wild rats was investigated in twenty-four provinces of Thailand during the period December 2011 to June 2014. Of the 669 wild rats sampled, 46 (6.88%) were infected with Angiostrongylus lungworms. The rodents harbouring A. cantonensis worms included Bandicota indica, Bandicota savilei, Rattus exulans, Rattus norvegicus, Rattus rattus complex and Rattus tiomanicus, and those harbouring A. malaysiensis were B. savilei, Rattus losea, R. norvegicus and R. rattus complex. No parasite was recovered from Maxomys surifer (n=11), Mus musculus (n=1), Niviventer fulvescens (n=2), Rattus argentiventer (n=4), Rattus nitidus (n=3) and Sundamys muelleri (n=3). In positive rats, the incidence of infection with Angiostrongylus lungworms was variable among host species and provinces. There were also considerable variation in the proportion of male and female worms among rodent hosts and localities. Two hundred and thirty-five of the collected worms were male and 282 were female. The mean worm burden in the positive rats was 11.24 and ranged from 1 to 61. 81.82% (423/517) of the adult worms were morphologically identified as A. cantonensis, and 18.18% (94/517) were A malaysiensis. One R. rattus from Prachuap Khiri Khan had mixed infection of A. cantonensis and A. malaysiensis (10 worms of each species). The overall number of male (202) and female (221) A. cantonensis worms was not significantly different (χ2 = 0.86, 0.50 > P > 0.30). However, the overall number of male (33) and female (61) A. malaysiensis worms was significantly different (χ2 = 8.34, P < 0.01). The present study added one new definitive host (R. tiomanicus) for A. cantonensis and two new definitive hosts (B. savilei and R. losea) for A. malaysiensis in Thailand. Our data update and contribute significantly to existing knowledge of the geographical distribution of A. cantonensis in wild rats in Thailand and confirm the occurrence of A. malaysiensis throughout the country.

Dot immunogold filtration assay (DIGFA) for the rapid detection of specific antibodies against the rat lungworm Angiostrongylus cantonensis (Nematoda: Metastrongyloidea) using purified 31-kDa antigen.

A rapid dot immunogold filtration assay (DIGFA) was adopted for specific immunodiagnosis of human cerebral angiostrongyliasis, using purified 31-kDa glycoprotein specific to Angiostrongylus cantonensis as diagnostic antigen and protein A colloidal gold conjugate as antigen-antibody detector. A total of 59 serum samples were assayed - 11 samples from clinically diagnosed patients with detectable A. cantonensis-specific antibody in immunoblotting; 23 samples from patients with other related parasitic diseases, i.e. gnathostomiasis (n= 8), cysticercosis (n= 5), toxocariasis (n= 2), filariasis (n= 4), paragonimiasis (n= 2) and malaria (n= 2); and 25 samples from normal healthy subjects. The sensitivity and specificity of DIGFA to detect anti-A. cantonensis specific antibodies in serologically confirmed angiostrongyliasis cases, were both 100%. No positive DIGFA was observed in cases with other parasitic diseases, and the healthy control subjects. The 3-min DIGFA is as sensitive and specific as the 3-h immunoblot test in angiostrongyliasis confirmed cases that revealed a 31-kDa reactive band. The gold-based DIGFA is more rapid and easier to perform than the traditional enzyme-linked immunosorbent assay (ELISA). The test utilizing purified A. cantonensis antigen is reliable and reproducible for specific immunodiagnosis of human infection with A. cantonensis - thus can be applied as an additional routine test for clinical diagnostic support. Large-scale sero-epidemiological studies in endemic communities in north-east Thailand are under way to evaluate its usefulness under field conditions.

A report case of Cyclospora and Cryptosporidium mixed infection in a HIV-negative child in Thailand.

The first case of cyclosporosis in a non HIV-infected child in Thailand, co-infected with Cryptosporidium, was reported. The patient was a 3 year-old malnourished orphan who presented with fever, abdominal distension and relapsing diarrhea. There was no leukocyte in her stool, however, numerous Cyclospora and Cryptosporidium oocysts were identified by modified acid-fast staining. The illness was cured by co-trimoxazole and fluid therapy. More coccidial infections in Thailand may be detected if modified acid-fast staining is routinely performed.

Intestinal parasitic infections among human immunodeficiency virus-infected and -uninfected children hospitalized with diarrhea in Bangkok, Thailand.

A prospective observational study was conducted to determine the prevalence and the clinical impact of intestinal parasitic infections in diarrheal illness among HIV-infected and HIV-uninfected children hospitalized with diarrhea in Bangkok, Thailand. Stool samples were examined for intestinal parasites using a simple smear method, a formalin-ether concentration method, a modified acid-fast stain and a modified trichrome stain. Intestinal parasites (IP) were identified in the stool specimens of 27 of 82 (33%) HIV-infected and 12 of 80 (15%) HIV-uninfected children (p=0.01). Microsporidia and Cryptosporidium were the most common IP found. Eighty-two percent of HIV-infected and 97% of HIV-uninfected groups presented with acute diarrhea and 76% of each group had watery diarrhea. Pneumonia was the most common concurrent illness, found in 22%. Clinical findings were unable to differentiate children infected with IP. Sixty-three percent of HIV-infected and 83% of HIV-uninfected children who had IP made a satisfactory recovery without specific anti-parasitic therapy. However, 9 children (7 HIV-infected and 2 HIV-uninfected) with persistent diarrhea who also had cryptosporidiosis and/or microsporidiosis did not respond to azithromycin and/or albendazole respectively. HIV-infected children with cryptosporidiosis were older and had more advanced HIV infection than those with microsporidiosis. Routine stool examination for IP should be considered due to the absence of clinical markers. The lack of effective therapy for the major IP found underscores the importance of preventive measures.

Toxoplasma gondii antibodies in HIV and non-HIV infected Thai pregnant women.

Serological evidence for Toxoplasma gondii infection in Thai pregnant women was investigated. One thousand six hundred and sixty-nine blood specimens were collected from 838 HIV-seropositive and 831 HIV-seronegative pregnant women attending the antenatal-care clinic at Siriraj Hospital, Bangkok, Thailand, during a two-year period. Toxoplasma IgG antibody was detected, using a solid-phase enzyme-linked immunosorbent assay in which the membrane protein p-30 was the predominant antigen. IgG positive sera were subsequently examined for IgM antibody by the capture antibody enzyme immunoassay. The IgG antibody was found in 450 (53.7%) HIV seropositive women and 44 (5.3%) non-HIV infected women, with a statistically significant difference (p < 0.0001). Three of the 450 HIV-seropositive and 2 of the 44 HIV-seronegative sera with IgG antibody were positive for IgM antibody against T. gondii. This result suggested that HIV seropositive pregnant women had a higher risk of Toxoplasma infection with increase exposure to their offspring.

Treatment of acanthamoeba keratitis with chlorhexidine.

OBJECTIVE: To evaluate the efficacy of chlorhexidine solution in the treatment of patients with Acanthamoeba keratitis. DESIGN: Prospective nonrandomized study. PARTICIPANTS: Five patients infected with culture-proven Acanthamoeba keratitis. INTERVENTION: Chlorhexidine solution was used hourly on six eyes and gradually reduced to four times a day after 1 month. Follow-up ranged from 1 to 10 months (mean, 4 months). MAIN OUTCOME MEASURES: Severity of symptoms and signs, time for healing, and final visual acuity. RESULTS: Clinical results in four patients showed improved visual acuity, with a rapid recovery within 1 week. No adverse drug reaction was encountered, but one patient with a perforated ulcer developed glaucoma. Eighty-three percent of 6 eyes were medically cured with chlorhexidine and recovered visual acuity 6/18 or better. Four of five patients improved within 3 weeks, with resolution of infiltration and healing of epithelial defects. By 2 to 3 weeks, visual acuity 6/18 or better had improved in four (66.7%) of six eyes and recovered 6/6 in two eyes (33.3%). Bacterial coinfection occurred in one eye. CONCLUSION: Chlorhexidine dramatically hastened clinical improvement in all eyes and is a successful medical therapy that has excellent results in patients who are diagnosed early.

Pneumocystis carinii severe pneumonia among human immunodeficiency virus-infected children in Thailand: the effect of a primary prophylaxis strategy.

BACKGROUND: A knowledge of the epidemiology of Pneumocystis carinii pneumonia (PCP) is important for the development of a strategy for primary PCP prophylaxis and empiric treatment for severe pneumonia in HIV-infected children. However, little is known about the epidemiology of PCP in developing countries. Objective. To measure the relative rate of PCP among hospitalized HIV-infected children with severe pneumonia in Bangkok and evaluate the effect of a strategy of primary PCP prophylaxis in HIV-exposed infants. METHODS: All HIV-infected children hospitalized from January, 1996, to December, 1997, for severe pneumonia were investigated for PCP with the use of specimens obtained from bronchoalveolar lavage, endotracheal aspiration or lung tissue necropsy. Characteristics associated with severe pneumonia were described, and the differences between PCP and non-PCP in these severely ill children were analyzed. In June, 1996, a strategy of primary PCP prophylaxis using trimethoprim-sulfamethoxazole in all HIV-exposed infants from 1 to 6 month of age was initiated in our institution. The effect of this strategy was evaluated. RESULTS: Of 279 hospitalized HIV-infected children 128 (46%) were diagnosed with pneumonia and 26 (20%) of these had severe pneumonia. P. carinii was identified in 9 (35%) children with severe pneumonia. After June, 1996, the rate of severe pneumonia among all hospitalized children decreased from 16% from January through June, 1996, to 7% from July, 1996, through December, 1997 (P = 0.02). Cases of PCP decreased from 9 in 1996 to zero in 1997. The percentage of HIV-infected children receiving PCP prophylaxis at the time of admission increased from 53% before June, 1996, to 72% in late 1997 (P = 0.04). The overall percentage of patients with severe pneumonia receiving PCP prophylaxis at the time of admission was 34%. Breakthrough PCP occurred in 2 children with poor compliance. Patients with PCP were significantly younger than those without PCP (mean age, 10.6+/-10.6 vs. 29.8+/-28.3 months, P = 0.02). CONCLUSION: PCP occurred in one-third of cases of severe pneumonia in HIV-infected children in Bangkok. The data suggest that PCP prophylaxis can prevent both PCP and non-PCP.

Intestinal microsporidiosis in HIV infected patients with chronic diarrhea in Thailand.

Microsporidia have been recognized as emerging opportunistic agents affecting multiple organs. Intestinal microsporidiosis caused by Enterocytozoon bieneusi and Encephalitozoon intestinalis is a common disease which is associated with gastrointestinal symptoms, particularly in AIDS patients. So far, information on the frequency of this enteric disease in Thailand is not available. Therefore, the present study was undertaken to investigate the prevalence of intestinal microsporidiosis in HIV infected persons with chronic diarrhea. From 1995 to 1996, multiple diarrheal stool specimens were received and examined for the presence of the organism using Weber's modified trichrome staining method and transmission electron microscopy for confirmation. Twenty-two of 66 patients (33.3%) were positive for microsporidia which appeared as pink-red spores of 0.8-1.2 x 0.7-0.9 microm with the characteristic transverse or oblique band representing the coiled polar filament. Clinical features of these patients included chronic diarrhea (100%), weight loss (100%), abdominal pain (77%), fever (36%), vomiting (36%) and anorexia (18%). Transmission electron microscopic examination of fecal specimens from the 22 patients with positive staining results revealed E. bieneusi in 18 cases.

Causes of chronic diarrhea in patients with AIDS in Thailand: a prospective clinical and microbiological study.

A prospective study was designed to investigate the causes of chronic diarrhea in AIDS patients in Thailand. Forty-five patients from Bamrasnaradura Infectious Diseases Hospital were enrolled. Extensive investigations included multiple stool examinations for ova and parasites, using the stool formalin-ether concentration method, stool culture, stool acid-fast bacilli (AFB) stain, stool modified AFB stain, esophagogastroduoscopy with duodenal aspirate and biopsy, and colonoscopy with biopsy. Biopsied specimens were examined with H&E, Giemsa, Gram, Periodic acid Schiff, and AFB stains. Definitive causes were found in 29 patients (64.4%). Of these 29, 7 patients were found to habor more than 1 pathogen (15.5%). The most commonly found enteric pathogen was Cryptosporidium parvum (20.0%). Less frequently found pathogens were Mycobacterium tuberculosis (17.8%), Salmonella spp. (15.5%), Cytomegalovirus (11.1%), Mycobacterium avium intracellulare (6.6%), Strongyloides stercoralis (4.4%), Giardia lamblia (4.4%), Cryptococcus neoformans (2.2%), Histoplasma capsulatum (2.2%), Campylobacter jejun (2.2%), and Cyclospora cayetanensis (2.2%). Salmonella spp., Mycobacterium tuberculosis, and Mycobacterium avium intracellulare infections were shown to be more common in Thailand than in African countries.