Assessment of an Immuno-Diagnostic Method for Hookworm-Related Cutaneous Larva Migrans Using Crude Extracts of Ancylostoma caninum.

People can become infected with cutaneous larva migrans (CLM) through skin penetration by the infective zoonotic larvae of hookworms. Few studies have investigated CLM's immunodiagnosis, and the existing studies were limited to crude somatic or excretory/secretory antigens (Ags) from adult worms. Here, we aimed to develop an indirect enzyme-linked immunosorbent assay (ELISA) to differentiate and diagnose hwCLM by detecting immunoglobulin (Ig)E, IgG, and IgG subclasses 1-4 (IgG1-4) against the somatic Ag of adult Ancylostoma caninum checkerboard titrations of adult A. caninum worm extract. Pooled serum controls were immunocharacterized using an indirect ELISA. The IgG1-4 and IgE results were unsatisfactory; however, the use of total IgG achieved results comparable to those of immunoblotting. Thus, we continued to analyze the IgG-ELISA using serum samples from patients with hwCLM and heterologous infections as well as from healthy controls. The sensitivity and excellent specificity of the total IgG-ELISA were 93.75% and 98.37%, respectively, and its positive and negative predictive values were 75% and 99.67%, respectively. Antibodies from five cases of angiostrongyliasis, gnathostomiasis, and dirofilariasis cross-reacted with the somatic Ag of adult A. caninum. This new assay can adequately serodiagnose hwCLM when combined with clinical features and/or histological examination.

Prevalence and Subtype Distribution of Blastocystis Isolated from School-Aged Children in the Thai-Myanmar Border, Ratchaburi Province, Thailand.

Blastocystis is one of the most common enteric protozoa that inhabits the intestinal tract of humans and different animals. Moreover, it has a worldwide geographic distribution. Its main mode of transmission is via the fecal-oral route. At present, 26 subtypes are widely distributed across both humans and animals. The current study aimed to determine the prevalence and subtype distribution of Blastocystis among school-aged children living on the Thai-Myanmar border, Ratchaburi province, Thailand. In total, 508 samples were collected from children at six schools. The prevalence of Blastocystis infection was amplified and sequenced in the 600 bp barcode region of the small-subunit ribosomal RNA (SSU rRNA). The overall prevalence of Blastocystis infection was 3.35% (17/508). ST3 (11/17) was the most predominant subtype, followed by ST1 (5/17) and ST2 (1/17). A phylogenetic tree was constructed based on the Tamura92+G+I model using the maximum-likelihood algorithm. Surprisingly, all sequences of the ST3-positive samples were closely correlated with the cattle-derived sequence. Meanwhile, all sequences of the Blastocystis ST1-positive samples were closely correlated with the human-derived sequence. Nevertheless, further studies should be conducted to validate the zoonotic transmission of Blastocystis. Based on our findings, personal hygiene and sanitation should be improved to promote better health in children in this area.

Molecular identification of Pentatrichomonas hominis in animals in central and western Thailand.

BACKGROUND: Pentatrichomonas hominis inhabits the digestive tracts of several vertebrates, such as humans, monkeys, pigs, dogs, cats and rats. This protozoan was originally considered a commensal of the digestive tract but has subsequently been identified as a potential zoonotic parasite and a causative agent of diarrhoea. Molecular techniques are considered more sensitive and specific to detect P. hominis. This study aimed to determine the presence and genetic diversity of P. hominis in animals in Thailand. A total of 403 faecal samples were collected from 119 cats, 55 dogs, 73 goats, 35 monkeys, 55 cattle and 66 pigs, and the presence of P. hominis was determined using the nested polymerase chain reaction method. Sequence analysis of small-subunit ribosomal RNA genes was used to determine the genotype of the organism. RESULTS: Twenty-six samples (26/403, 6.45%) were positive for P. hominis. The highest prevalence was found in cats (21/119; 17.65%), followed by cattle (3/55; 5.45%) and dogs (2/55; 3.64%). Seven out of 26 nucleotides demonstrated 100% sequence identity with existing sequences; additionally, 16 novel sequence patterns were identified. All nucleotide sequences of P. hominis-positive samples were shown in the same branch with the previously described P. hominis sequences found in humans, dogs and goat. CONCLUSION: This is the first study on P. hominis infections in animals in Thailand. Our findings revealed that the prevalence of P. hominis was significantly higher in cats than in cattle and dogs. Cats were the main reservoir host; however, P. hominis can infect several kinds of animals. Therefore, the proper waste management of animals is necessary to reduce and prevent infection in the community.

Development of a rapid, simple method for detecting Naegleria fowleri visually in water samples by loop-mediated isothermal amplification (LAMP).

Naegleria fowleri is the causative agent of the fatal disease primary amebic meningoencephalitis. Detection of N. fowleri using conventional culture and biochemical-based assays is time-consuming and laborious, while molecular techniques, such as PCR, require laboratory skills and expensive equipment. We developed and evaluated a novel loop-mediated isothermal amplification (LAMP) assay targeting the virulence-related gene for N. fowleri. Time to results is about 90 min and amplification products were easily detected visually using hydroxy naphthol blue. The LAMP was highly specific after testing against related microorganisms and able to detect one trophozoite, as determined with spiked water and cerebrospinal fluid samples. The assay was then evaluated with a set of 80 water samples collected during the flooding crisis in Thailand in 2011, and 30 natural water samples from border areas of northern, eastern, western, and southern Thailand. N. fowleri was detected in 13 and 10 samples using LAMP and PCR, respectively, with a Kappa coefficient of 0.855. To the best of our knowledge, this is the first report of a LAMP assay for N. fowleri. Due to its simplicity, speed, and high sensitivity, the LAMP method described here might be useful for quickly detecting and diagnosing N. fowleri in water and clinical samples, particularly in resource-poor settings.

Subtype distribution of Blastocystis in Thai-Myanmar border, Thailand.

Blastocystis sp. is a common zoonotic intestinal protozoa which has been classified into 17 subtypes (STs). A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis in villagers living on the Thai-Myanmar border, where the risk of parasitic infection is high. A total of 207 stool samples were collected and DNA was extracted. PCR and sequencing using primers targeting small-subunit ribosomal RNA (SSU rRNA) gene were performed. The prevalence of Blastocystis infection was 37.2% (77/207). ST3 (19.8%; 41/207) was the predominant subtype, followed by ST1 (11.6%; 24/207), ST2 (5.3%; 11/207), and ST4 (0.5%; 1/207). A phylogenetic tree was reconstructed using the maximum likelihood (ML) method based on the Hasegawa-Kishino-Yano + G + I model. The percentage of bootstrapped trees in which the associated taxa clustered together was relatively high. Some sequences of Blastocystis positive samples (TK18, 39, 46, 71, and 90) were closely related to animals (pig and cattle) indicating zoonotic risks. Therefore, proper health education in parasitic prevention for the villagers should be promoted to improve their personal hygiene. Further longitudinal studies are required to monitor the prevalence of parasitic infections after providing health education and to investigate Blastocystis ST in animals living in these villages.

Molecular identification of Cryptosporidium spp. in seagulls, pigeons, dogs, and cats in Thailand.

Zoonotic Cryptosporidium spp., particularly C. meleagridis, C. canis, and C. felis, are enteric protozoa responsible for major public health concerns around the world. To determine the spread of this parasite in Thailand, we conducted molecular identification of Cryptosporidium spp. from animal samples around the country, by collecting and investigating the feces of seagulls (Chroicocephalus brunnicephalus and Chroicocephalus ridibundus), domestic pigeons (Columba livia domestica), dogs, and cats. Seagull and pigeon samples were collected at the seaside and on the riverside to evaluate their potential for waterborne transmission. Ten pigeon samples were combined into one set, and a total of seven sets were collected. Seventy seagull samples were combined into one set, and a total of 13 sets were collected. In addition, 111 dog samples were collected from cattle farms, and 95 dog and 80 cat samples were collected from a temple. We identified C. meleagridis in pigeons, Cryptosporidium avian genotype III in seagulls, C. canis in dogs, and C. felis in cats. In the temple, the prevalence was 2.1% (2/95) for dogs and 2.5% (2/80) for cats. No Cryptosporidium was found in dog samples from cattle farms. These are the first findings of C. meleagridis in domestic pigeons, and Cryptosporidium avian genotype III in seagulls. Our study invites further molecular epidemiological investigations of Cryptosporidium in these animals and their environment to evaluate the public health risk in Thailand.

Seasonal variation and potential sources of Cryptosporidium contamination in surface waters of Chao Phraya River and Bang Pu Nature Reserve pier, Thailand.

Using molecular techniques, a longitudinal study was conducted with the aims at identifying the seasonal difference of Cryptosporidium contamination in surface water as well as analyzing the potential sources based on species information. One hundred forty-four water samples were collected, 72 samples from the Chao Phraya River, Thailand, collected in the summer, rainy and cool seasons and 72 samples from sea water at Bang Pu Nature Reserve pier, collected before, during and after the presence of migratory seagulls. Total prevalence of Cryptosporidium contamination in river and sea water locations was 11% and 6%, respectively. The highest prevalence was observed at the end of rainy season continuing into the cool season in river water (29%) and in sea water (12%). During the rainy season, prevalence of Cryptosporidium was 4% in river and sea water samples, but none in summer season. All positive samples from the river was C. parvum, while C. meleagridis (1), and C. serpentis (1) were obtained from sea water. To the best of our knowledge, this is the first genetic study in Thailand of Cryptosporidium spp contamination in river and sea water locations and the first report of C. serpentis, suggesting that humans, household pets, farm animals, wildlife and migratory birds may be the potential sources of the parasites. The findings are of use for implementing preventive measures to reduce the transmission of cryptosporidiosis to both humans and animals.

Obtaining an isolate of Ancylostoma braziliense from cats without the need for necropsy.

Because the eggs of Ancylostoma species of dogs and cats are difficult to readily distinguish morphologically, isolation of a certain species often requires the humane death of the source animal or holding an animal after treatment to obtain worms for specific identification or to harvest ex utero eggs. The objective of this study was to obtain an isolate of Ancylostoma braziliense from 1-time, field-collected samples of feline feces without the need for the killing of any animals. During a collection trip to Florida, fecal samples (n  =  40) were collected and identified as containing A. braziliense eggs (n  =  26) using centrifugal sugar flotation. Eggs from hookworm-positive slides were washed into tubes, DNA was extracted, and 10 samples were identified as containing A. braziliense using restriction fragment length polymorphism (RFLP) with Hinf1. Six of these samples also contained DNA of Ancylostoma tubaeforme and, thus, only 4 samples were from cats infected only with A. braziliense. Larvae cultured from two of the latter samples were used to subcutaneously inoculate a purpose-bred puppy with the intention to inhibit the growth of any potentially contaminating A. tubaeforme larvae in the culture. The infection was patent at 14 days after inoculation, and the eggs were identified as A. braziliense by RFLP and DNA sequencing. Larvae were cultured from the feces of this dog and used to infect a laboratory-reared, specific-pathogen-free cat; the eggs and larvae produced by the cat were also identified molecularly as those of A. braziliense. The larvae from this cat were used to infect other cats to maintain the isolate for further research. Both the puppy and the first cat used in this study were treated to clear their infections and have since been adopted by new owners.

Prevalence of Ancylostoma braziliense in cats in three northern counties of Florida, United States.

A convenience sampling of fecal specimens from 40 cats in northern Florida was examined for the presence of Ancylostoma braziliense eggs by using centrifugal sugar flotation and polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Of the 40 samples, 26 (65%) contained hookworm eggs. DNA from 24 samples was successfully amplified using PCR; using RFLP, 10 samples were identified as containing DNA of A. braziliense (41.7% of the 24 samples that successfully amplified). Of these, 6 samples contained DNA of both Ancylostoma tubaeforme and A. braziliense, and 4 samples contained only DNA of A. braziliense. The remaining samples (n  =  14) contained only the DNA of A. tubaeforme, except for 1 sample that had no discernible bands after RFLP.

Cryptosporidium oocyst detection in water samples: floatation technique enhanced with immunofluorescence is as effective as immunomagnetic separation method.

Cryptosporidium can cause gastrointestinal diseases worldwide, consequently posing public health problems and economic burden. Effective techniques for detecting contaminated oocysts in water are important to prevent and control the contamination. Immunomagnetic separation (IMS) method has been widely employed recently due to its efficiency, but, it is costly. Sucrose floatation technique is generally used for separating organisms by using their different specific gravity. It is effective and cheap but time consuming as well as requiring highly skilled personnel. Water turbidity and parasite load in water sample are additional factors affecting to the recovery rate of those 2 methods. We compared the efficiency of IMS and sucrose floatation methods to recover the spiked Cryptosporidium oocysts in various turbidity water samples. Cryptosporidium oocysts concentration at 1, 10(1), 10(2), and 10(3) per 10 microl were spiked into 3 sets of 10 ml-water turbidity (5, 50, and 500 NTU). The recovery rate of the 2 methods was not different. Oocyst load at the concentration < 10(2) per 10 ml yielded unreliable results. Water turbidity at 500 NTU decreased the recovery rate of both techniques. The combination of sucrose floatation and immunofluorescense assay techniques (SF-FA) showed higher recovery rate than IMS and immunofluorescense assay (IMS-FA). We used this SF-FA to detect Cryptosporidium and Giardia from the river water samples and found 9 and 19 out of 30 (30% and 63.3%) positive, respectively. Our results favored sucrose floatation technique enhanced with immunofluorescense assay for detecting contaminated protozoa in water samples in general laboratories and in the real practical setting.