Hepatitis C virus (HCV) subtype prevalence in Chiang Mai, Thailand, and identification of novel subtypes of HCV major type 6.

Subtype analysis of hepatitis C viruses (HCVs) obtained from patients with chronic liver disease in Chiang Mai, Thailand, was performed. Of 46 HCV isolates, 13 (28%) were shown to belong to HCV subtype 3a (HCV-3a), 10 (22%) to belong to HCV-1a, 7 (15%) to belong to HCV-1b, 1 (2%) to belong to HCV-3b, and 1 (2%) to belong to a variant group, as determined from partial nucleotide sequences of the NS5B region of the viral genome. Analysis of 5' untranslated region sequences identified five other isolates (11%) of HCV type 1 and two other isolates (4%) of type 3. Detailed phylogenetic positions for the variant described above and those previously obtained from blood donors and drug addicts in Chiang Mai were determined by a six-parameter neighbor-joining method on the basis of core, E1, and NS5B region sequences. The results revealed that those sequence variants represent novel subtypes of HCV type 6. The HCV type 6 isolates appear to be antigenically different from isolates of HCV types 1 and 2, as determined by a serotyping method that utilizes recombinant peptides corresponding to a portion of the NS4 protein. The significance of subtype analysis around this area is discussed.     

First case of cryptococcosis in a new species of bandicoot (Bandicota indica) caused by Cryptococcus neoformans var. grubii.

The first case of cryptococcosis caused by Cryptococcus neoformans var. grubii in a new species of bandicoot (Bandicota indica) is described. The animal was trapped in a bamboo thicket in a park located in the city of Jabalpur, India. On necropsy, pathological lesions were seen in the lungs and liver and C. neoformans var. grubii was isolated from the lungs, liver, kidneys, spleen and brain but not the heart or intestine. The soil of the animal's burrow and bamboo debris around it also revealed the presence of C. neoformans var. grubii. We hypothesize that the bandicoots may potentially act as sentinel animals for environmental human pathogenic Cryptococcus species.     

Applicability of presence-absence and sequential sampling for ovitrap surveillance of Aedes (Diptera: Culicidae) in Chiang Mai, northern Thailand

Applicability of presence or absence sampling for ovitrap surveillance of Aedes aegypti (L.) and Aedes albopictus (Skuse) was examined for data collected in Chiang Mai, northern Thailand. Distribution of eggs per trap was contagious but did not fit the negative binomial distribution with a common k. The relationship between the mean number of eggs per trap and the proportion of positive traps was described using Gerrard & Chiang's model, which does not assume particular distribution patterns. Using this relation, the mean number of eggs per trap with confidence limits can be estimated without egg counts. Potential usefulness of presence or absence sequential sampling for decision making (when to initiate vector control for prevention of dengue hemorrhagic fever) was shown.     

Profiles of HIV voluntary counseling and testing of clients at a district hospital,Chiang Mai Province,northern Thailand,from 1995 to 1999

Voluntary HIV counseling and testing (VCT) is a central component of comprehensive HIV prevention strategies targeting individual risk reduction. VCT data are essential for planning and improving HIV/AIDS intervention strategies. The objective of this study is to describe demographic profiles, reasons for seeking HIV counseling and testing, rate of declining HIV testing after pretest counseling, rate of failure to return for HIV test results, and HIV prevalence and associations among 3570 clients who sought VCT at Sansai Hospital in northern Thailand from 1995 to 1999. Data were abstracted retrospectively from client-level data recorded by the hospital counselors on a standard form. HIV prevalence was 29% and remained high throughout the study period. Reasons for seeking VCT for men and women were markedly different and highly correlated with rates of declining the test, failure to return for test results, and HIV prevalence. Declining VCT and failing to return were high among uneducated clients (p <.001). Failure to return among men was associated with HIV prevalence (OR = 1.72, p =.003), particularly for those who had risk behaviors (OR = 5.92, p <.001) and those who wanted to know their HIV serostatus (OR = 4.44, p =.002). Overall, VCT acceptance and returning for test results were high. VCT services at the community level can reach high-risk individuals, especially male partners of women tested as part of routine prenatal care.     

Genetic characterization of group C rotavirus isolated from a child hospitalized with acute gastroenteritis in Chiang Mai,Thailand

During an epidemiological survey of human rotavirus infection in Chiang Mai, Thailand, from 2002 to 2004, in which 263 stool specimens tested, one isolate of group C rotavirus was detected from a two-year-old child admitted to hospital with acute gastroenteritis. The human group C rotavirus, named CMH004/03, was characterized further by molecular analyses of its VP4, VP6, and VP7 gene segments as well as determination of RNA pattern by polyacrylamide gel electrophoresis (PAGE). Molecular characterization of VP4, VP6, and VP7 genes by sequence analyses showed high levels of sequence identities with those of human group C rotavirus reference strains isolated worldwide at 95.2% to 99.4% on nucleotide and 97.5% to 100% on amino acid levels. In contrast, the CMH004/03 strain exhibited far lesser nucleotide and amino acid sequence identities at 67.7% to 84.1% and 68.7% to 91.3%, respectively, when compared with those of porcine and bovine group C rotaviruses. Phylogenetic analyses of VP4, VP6, and VP7 genes clearly confirmed that the CMH004/03 strain clustered in a monophyletic branch with other human group C rotavirus reference strains and distantly related to the clusters of animal group C rotavirus strains. In addition, the RNA electrophoretic migration pattern of CMH004/03 showed a typical pattern (4-3-2-2) of group C rotavirus. To our knowledge, this study is the second report of group C rotavirus infection in pediatric patients in Thailand after it was reported for the first time about two decades ago.     

Genetic diversity of noroviruses and sapoviruses in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand

Human caliciviruses, including norovirus (NoV) and sapovirus (SaV), are recognized as common pathogens that cause acute viral gastroenteritis in children and adults throughout the world. To gain an overview of molecular epidemiology of human caliciviruses in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand, from 2002 to 2004, NoV and SaV were detected and characterized molecularly for identification of their genotypes. From a total of 248 fecal specimens collected, 35 (14.1%) were positive for NoV GII genogroup. Among the 35 NoV GII, GII/4 was the most predominant genotype (22 strains), followed by GII/3 (7 strains), GII/1 (2 strains), GII/7 (2 strains), GII/2 (1 strain), and GII/16 (1 strain). In addition, only three specimens (1.2%) were positive for SaV, each of which was classified into two different genogroups. One isolate was clustered with GIV genogroup, while the other two belonged to two distinct genotypes of the SaV GI cluster, GI/1 and GI/2 genotypes. This study demonstrated that human caliciviruses are important enteric viruses that caused acute gastroenteritis in the hospitalized children in Chiang Mai, Thailand from 2002 to 2004. Moreover, a great genetic diversities of NoV and SaV were observed.     

Analysis of hepatitis C virus isolates among healthy blood donors and drug addicts in Chiang Mai, Thailand.

Hepatitis C virus (HCV) isolates obtained from 25 anti-HCV antibody-positive healthy blood donors and 29 drug addicts in Chiang Mai, Thailand, were analyzed. HCV RNA was detected in 23 blood donor samples (92%) and 24 drug addict blood samples (83%) by PCR for a portion of the NS5 region. Subtype analysis revealed that HCV type 3a (HCV-3a) was the prevailing subtype (30%), which was followed in prevalence by HCV-1a (21%), -1b (13%), -3b (13%), and -6a (2%). Six (13%) of the 47 isolates showed low sequence similarities with known types and subtypes. The sequence variants could be grouped into four branches in a molecular evolutionary phylogenetic tree.     

Emergence of human G9 rotavirus with an exceptionally high frequency in children admitted to hospital with diarrhea in Chiang Mai, Thailand

Among 315 fecal specimens collected from children hospitalized with diarrhea in Chiang Mai, Thailand, in 2000-2001, group A rotavirus was detected in 107 (34.0%). Of these, 98 (91.6%) were G9, 6 (5.6%) were G3 and 3 (2.8%) were G2, respectively. Identification of their P-types demonstrated that 103 (96.3%) were P[8], 3 (2.8%) were P[4], and 1 (0.9%) was P[3] genotypes. Determination of G- and P-type combination revealed that all of G9 isolates were associated with P[8]. G9P[8] was the most predominant genotype and accounted for the majority (91.6%) of rotaviruses detected in this study. Molecular characterization of these G9 isolates demonstrated that all had long electropherotype, 96 of 98 (98.0%) belonged to subgroup II, one belonged to subgroup I and the other one was subgroup unidentifiable. All of G9 isolates possessed NSP4 genetic group B except for one isolate that showed dual genetic group specificities, B and C. The full-length VP7 gene nucleotide sequences among 15 representatives of these G9 strains were found to be highly homologous with percent identities of 99.3%-100%. Comparison with other G9 strains recently isolated showed that their nucleotide sequences were closely related to those of the US strain, US1205 (98.7%-99.0%) and Thai strain, 97CM108 (98.1%-99.0%). Interestingly, they were most closely related to the Japanese strain, 00-SG2509VP7, isolated in the same epidemic season, with percent nucleotide sequence identity of 99.4%-99.8%. The data imply that G9 strains isolated in this study and a G9 strain isolated in Japan in the year 2000 might have descended from the same ancestor.     

Essential oils as potential adulticides against two populations of Aedes aegypti, the laboratory and natural field strains, in Chiang Mai province, northern Thailand

Essential oils derived from five plant species, celery (Apium graveolens), caraway (Carum carvi), zedoary (Curcuma zedoaria), long pepper (Piper longum), and Chinese star anise (Illicium verum), were subjected to investigation of adulticidal activity against mosquito vectors. Two populations of Aedes aegypti, the laboratory and natural field strains, collected in Chiang Mai province, northern Thailand were tested in pyrethroid-susceptibility bioassays. The results revealed that the natural field strain of A. aegypti was resistant to permethrin, with mortality rates ranging from 51 to 66%. A mild susceptibility, with mortality rates ranging from 82 to 88%, was observed in the natural field strain of A. aegypti exposed to lambdacyhalothrin, which suggested that this strain was tolerant and might be resistant to this insecticide. However, laboratory-reared A. aegypti exposed to discriminating dosages of permethrin and lambdacyhalothrin induced 100% mortality in all cases, thus indicating complete susceptibility of this strain to these insecticides. The adulticidal activity determined by topical application revealed that all five essential oils exerted a promising adulticidal efficacy against both laboratory and natural field strains of A. aegypti. Although the laboratory strain was slightly more susceptible to these essential oils than the natural field strain, no statistically significant difference was observed. Moreover, comparison of the adulticidal activity indicated that the performance of these essential oils against the two strains of A. aegypti was similar. The highest potential was established from caraway, followed by zedoary, celery, long pepper, and Chinese star anise, with an LC₅₀ in the laboratory strain of 5.44, 5.94, 5.96, 6.21, and 8.52 μg/mg female, respectively, and 5.54, 6.02, 6.14, 6.35, and 8.83 μg/mg female, respectively, in the field strain. These promising essential oils are, therefore, an alternative in developing and producing mosquito adulticides as an effective measure used in controlling and eradicating mosquito vectors.     

Field evaluation of G10, a celery (<Emphasis Type="Italic">Apium graveolens</Emphasis>)-based topical repellent,against mosquitoes (Diptera: Culicidae) in Chiang Mai province,northern Thailand

The potential of G10, a celery (Apium graveolens)-based topical product, as a repellent against natural mosquito populations was evaluated in comparison to commercial (Insect Block 28) and standard (25% DEET) repellents in Chiang Mai province, northern Thailand. These repellent products afforded encouragingly excellent personal protection against a broad range of mosquito species belonging to various genera, including Aedes, Anopheles, Armigeres, Culex, and Mansonia. No mosquito bite was observed on the volunteers treated with G10 and Insect Block 28 throughout the field study, whereas two species, i.e., six A. barbirostris and two A. subalbatus, came to bite or land on 25% DEET-treated volunteers. Thus, it can be concluded that while G10 and Insect Block 28 exhibited similarly powerful repellent activities with complete (100%) protection, 25% DEET was effective in minimizing bites with 99.68% protection. G10 formula was also studied for physical properties and biological stability after being kept under two conditions; a heating and cooling cycle, and varying temperature and time storage. Most samples of stored G10 not only demonstrated a similarity in appearance and physical properties, but also provided comparable repellency to that of the fresh preparation. These findings encourage commercial development of G10 formula as an alternative to conventional synthetic repellents.     

Distribution of norovirus and sapovirus genotypes with emergence of NoV GII.P16/GII.2 recombinant strains in Chiang Mai,Thailand

Norovirus (NoV) and sapovirus (SaV) are recognized as the causative agents of acute gastroenteritis, and NoV is one of the leading pathogens reported worldwide. This study reports on the distribution of NoV and SaV genotypes in children hospitalized with acute gastroenteritis in Chiang Mai, Thailand, from January 2015 to February 2017. From a total of 843 stool samples, 170 (20.2%) and 16 (1.9%) were identified as having NoV and SaV infections, respectively. Two samples (0.2%) were positive for both NoV and SaV. Of these, NoV GII.4 (57.2%) was the dominant genotype, followed by GII.2, GII.3, GII.17, GII.6, GII.7, GII.13, GII.14, GII.15, GII.21, GI.6, and GI.5. Among the NoV GII.4 variants, Sydney 2012 was the dominant variant during the period 2015-2016, while the other variants detected in this study were Asia 2003 and New Orleans 2009. Interestingly, an increase of NoV GII.2 was observed in 2016 and 2017. Characterization of partial RNA-dependent RNA polymerase and VP1 nucleotide sequences of GII.2 strains revealed that more than half of the GII.2 strains circulating in 2016 and 2017 were recombinant strains of GII.P16/GII.2. For SaV, the majority of strains belonged to GI.1 (55.6%) and GI.2 (33.3%), while GII.5 accounted for 11.1%. In conclusion, this study demonstrates the diversity of NoV and SaV, and the emergence of NoV GII.P16/GII.2 recombinant strains in 2016 and 2017 in Chiang Mai, Thailand.     

Identification of a novel Babesia sp. from a sable antelope (Hippotragus niger Harris, 1838)

Babesiosis in a sable antelope (Hippotragus niger Harris, 1838) was first reported in 1930; the parasite was named Babesia irvinesmithi. Recently, specimens from an adult sable that presented with a sudden onset of disease and that subsequently died during immobilization were submitted for molecular characterization. Microscopic examination of thin blood smears revealed the presence of small piroplasms. DNA was extracted from blood samples; the V4 variable region of the 18S rRNA gene was amplified and analyzed using the reverse line blot (RLB) assay. Amplicons did not hybridize with any of the Babesia or Theileria species-specific probes present on the blot and hybridized only with a Babesia or Theileria genus-specific probe, suggesting the presence of a novel species. The full-length 18S rRNA gene sequence was obtained and aligned with published sequences of related genera, and phylogenetic trees were constructed. Sequence similarity analyses indicated that a Babesia species, designated Babesia sp. (sable), was present. The sequence showed its highest similarity to B. orientalis and to an unnamed Babesia species previously detected in bovine samples. The latter was later established to be Babesia occultans. A Babesia sp. (sable)-specific RLB oligonucleotide probe was designed and used to screen 200 South African sable samples, but so far, no other sample has been found to be positive for the presence of Babesia sp. (sable) DNA. In summary, we identified a novel piroplasm parasite from a sable antelope that died from an unknown illness. While the parasite was observed in blood smears, there is no direct evidence that it was the cause of death.     

A new species of Leptotrombidium (Acari: Trombiculidae) collected from black plates in Thailand

A new species, Leptotrombidium (Leptotrombidium) dendrium, is described and illustrated. Specimens were collected from black plates exposed on the ground surface in a secondary forest at Nakhonratchasima and Surin Provinces in northeastern Thailand.