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.

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.

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.

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.

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 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.

Use if touch preparation as a rapid diagnosis of cutaneous leishmaniasis.

The definite diagnosis of cutaneous leishmaniasis depends on demonstration of the parasites in tissue fluid or pus from the nodule of ulcer. The touch preparation from the skin biopsy specimen is among methods of demonstration of the tissue parasites. This method could be done easily along with skin biopsy for histopathological study. Geimsa’s Wright’s stain were the appropriate staining technique. We have reported one case of cutanous leishmaniasis which showed that touch preparation was more sensitive than the scraping technique in detecting parasites in tissue. Touch preparation could be used as a diagnostic tool and adjuvant method to follow up the course of cutaneous leishmaniasis patient.