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Tropical medicine and health [journal]
- Severe Neurotoxic Envenoming and Cardiac Complications after the Bite of a 'Sind Krait' (Bungarus cf. sindanus) in Maharashtra, India. [Journal Article]
- Trop Med Health 2012 Sep; 40(3):103-8.
We report a case of severe envenoming with unusual complications and two anecdotal cases of fatalities following proven 17-scale-row 'Sind krait' (Bungarus cf. sindanus) bites on people sleeping in temporary huts at construction sites in Pune District, Maharashtra, India. A 25-yr-old male developed progressive neuromuscular paralysis, abdominal pain and autonomic disturbances complicated by four prolonged episodes of pulseless ventricular tachycardia requiring defibrillation, and followed by pulmonary edema secondary to impaired left ventricular systolic function and hyperfusion. There was no response to antivenom; mechanical ventilation was required for six days. Only one other case of fatal envenoming likely caused by this species had been reported previously in India. The distribution of B. sindanus sensu lato from eastern Afghanistan to India overlaps with that of the superficially very similar common krait (Bungarus caeruleus). Thus, B. cf. sindanus envenoming may be common but routinely overlooked or misdiagnosed.
- Immunoproteomics Identification of Major IgE and IgG4 Reactive Schistosoma japonicum Adult Worm Antigens Using Chronically Infected Human Plasma. [Journal Article]
- Trop Med Health 2012 Sep; 40(3):89-102.
Immunoepidemiological studies from endemic areas have revealed age-dependent resistance correlation with increased level of IgE and decreased level of IgG4 antibodies in responses to schistosomes' soluble worm antigen. However, there have been limited studies on analyses of major antigens that provoke IgE and IgG4 immune response during chronic stage of schistosomiasis. In this study, for the first time, immunoproteomics approach has been applied to identify S. japonicum worm antigens in liquid fractions that are recognized by IgE and IgG4 antibody using plasma from chronically infected population. ProteomeLabPF 2D fractionated 1-D and 2-D fractions of SWA antigens were screened using pooled high IgE/IgG4 reactive plasma samples by dot-blot technique. In 1-D fractions, IgE isotype was detected by fewer antigenic fractions (43.2%). The most recognized isotype was IgG3 (79.5%) followed by IgG1 (75.0%) and IgG4 (61.4%). Liquid chromatography MS/MS protein sequencing of reactive 2-D fractions revealed 18 proteins that were identified, characterized and gene ontology categories determined. 2-D fractions containing proteins such as zinc finger, RanBP2-type, domain-containing protein were strongly recognized by IgE and moderately by IgG4 whereas fractions containing proteins such as ubiquitin-conjugating enzyme and cytosolic II 5'-nucleotidase strongly recognizing by IgG subclasses (IgG1, IgG3 and IgG4) but not IgE. By this study, a simple and reproducible proteomic method has been established to identify major immunoreactive S. japonicum antigens. It is anticipated that this will stimulate further research on the immunogenicity and protective potential of proteins identified as well as discovery of novel compounds that have therapeutic importance.
- Positive Diversifying Selection on the Plasmodium falciparumsurf Gene in Thailand. [Journal Article]
- Trop Med Health 2012 Sep; 40(3):79-89.
Plasmodium falciparum SURFIN(4.1) is a type I transmembrane protein thought to locate on the merozoite surface and to be responsible for a reversible adherence to the erythrocyte before invasion. In this study, we evaluated surf(4.1) gene segment encoding extracellular region for polymorphism, the signature of positive selection, the degree of linkage disequilibrium, and temporal change in allele frequency distribution in P. falciparum isolates from Thailand in 1988-89, 2003, and 2005. We found that SURFIN(4.1) is highly polymorphic, particularly at the C-terminal side of the variable region located just before a predicted transmembrane region. A signature of positive diversifying selection on the variable region was detected by multiple tests and, to a lesser extent, on conserved N-terminally located cysteine-rich domain by Tajima's D test. Linkage disequilibrium between sites over a long distance (> 1.5 kb) was detected, and multiple SURFIN(4.1) haplotype sequences detected in 1988/89 still circulated in 2003. Few of the single amino acid polymorphism allele frequency distributions were significantly different between the 1988/89 and 2003 groups, suggesting that the frequency distribution of SURFIN(4.1) extracellular region remained stable over 14 years.
- Stable Allele Frequency Distribution of the Plasmodium falciparum clag Genes Encoding Components of the High Molecular Weight Rhoptry Protein Complex. [Journal Article]
- Trop Med Health 2012 Sep; 40(3):71-7.
Plasmodium falciparum Clag protein is a candidate component of the plasmodial surface anion channel located on the parasite-infected erythrocyte. This protein is encoded by 5 separated clag genes and forms a RhopH complex with the other components. Previously, a signature of positive diversifying selection was detected on the hypervariable region of clag2 and clag8 by population-based analyses using P. falciparum originating from Thailand in 1988-1989. In this study, we obtained the sequence of this region of 3 clag genes (clag2, clag8, and clag9) in 2005 and evaluated the changes over time in the frequency distribution of the polymorphism of these gene products by comparison with the sequences obtained in 1988-1989. We found no difference in the frequency distribution of 18 putatively neutral loci between the 2 groups, evidence that the background of the parasite population structure has remained stable over 14 years. Although the frequency distribution of most of the polymorphic sites in the hypervariable region of Clag2, Clag8, and Clag9 was stable over 14 years, we found that a proportion of the major Clag2 group and one amino acid position of Clag8 changed significantly. This may be a response to a certain type of pressure.
- Erratum. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):63.
[This corrects the article on p. 15-17 in vol. 40.].
- Ethnicity and delay in measles vaccination in a nairobi slum. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):59-62.
The influence of ethnicity on vaccination uptake in urban slums in Kenya is largely unknown. We examined the disparities in timeliness and coverage of measles vaccination associated with ethnicity in the Korogocho slum of Nairobi. The study used data from the Maternal and Child Health component of the Urbanization, Poverty and Health Dynamics Research Programme undertaken in the Korogocho and Viwandani slums by the African Population and Health Research Center from 2006 to 2010. Vaccination information was collected from children recruited into the study during the first year after birth, and a sub-sample of 2,317 who had been followed throughout the period and had the required information on measles vaccination was included in the analysis. Cox regression analysis was used to determine the association of ethnicity with delayed measles in the slum. We found significant disparities in the coverage and timeliness of measles vaccination between the ethnic groups in Korogocho. The Luhya and minor ethnic groups in the slum were more likely than the Kikuyu to have delayed measles vaccination. Ethnic groups with a high proportion of children with delayed measles vaccination need to be targeted to address cultural barriers to vaccination as part of efforts to improve coverage in urban slums.
- Distribution of Two Subgroups of Human T-Lymphotropic Virus Type 1 (HTLV-1) in Endemic Japan. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):55-8.
Endemic areas of human T-lymphotropic virus type 1 (HTLV-1) have been reported in Japan as well as tropical Africa, Central and South America and Melanesia. The existence of two subgroups, i.e., the transcontinental and Japanese subgroups, was reported in Japan. In the present study, we provide data on the ratio of the two subgroups in each endemic area and infection foci and examine the distribution of HTLV-1 in Japan and neighboring areas. A 657 bp fragment of env region of HTLV-1 proviral genome was successfully amplified for 183 HTLV-1 positive DNA samples. The subgroup determination was done by RFLP reactions using endonucleases HpaI and HinfI. The northern part of mainland Kyushu, represented by Hirado and Kumamoto, was monopolized by the Japanese subgroup, while the transcontinental subgroup ranged from 20 to 35% in the Pacific coast areas of Shikoku (Kochi), the Ryukyu Archipelago (Kakeroma and Okinawa) and Taiwan. An interesting finding in the present study is the presence of the transcontinental subgroup in Kochi, suggesting the endemicity of the transcontinental subgroup along the Kuroshio Current.
- One Injection of DsRed Followed by Bites from Transgenic Mosquitoes Producing DsRed in the Saliva Elicits a High Titer of Antibody in Mice. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):47-52.
It has been proposed that transgenic mosquitoes can be used as a "flying syringe" for infectious disease control. We succeeded in generating a transgenic (TG) mosquito, Anopheles stephensi, excreting and discharging DsRed in saliva. DsRed was deposited on the membrane where the TG mosquito probed with its proboscis. Repeated feeding by the TG mosquitoes induced anti-DeRed as well as anti-SG antibodies in mice. This indicates that the TG mosquitoes can immunize the animal. Moreover, in this report, we employed a pre-immunization method before exposing mice to the TG mosquitoes. We injected DsRed to mice to prepare memory B cells and exposed the mice to bites by the TG mosquitoes excreting DsRed. The mice produced a higher titer of antibody to DsRed, suggesting that the bites from TG mosquitoes act as a booster and that primary immunization with a vaccine protein and exposure to TG mosquitoes excreting the vaccine protein in the saliva produces a synergistic effect.
- Preservation of wild isolates of human malaria parasites in wet ice and adaptation efficacy to in vitro culture. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):37-45.
Wild isolates of malaria parasites were preserved in wet ice for 2-12 days and cultivated by a candle jar method. In four isolates of Plasmodium falciparum collected from Myanmar and preserved for 12 days, all failed to grow. In 31 isolates preserved for 5-10 days, nine were transformed to young gametocytes, but 22 isolates grew well. From Ranong, Thailand, nine isolates preserved for 7 days were examined, and six grew well. On the other hand, all of the 59 isolates collected from eastern Indonesian islands failed to establish as culture-adapted isolates, even most of them were preserved only for 2-3 days: 10 isolates stopped to grow, and 49 isolates were transformed to sexual stages by Day 10. These results indicated that a great difference in adaptation to in vitro culture may exist between wild isolates distributed in continental Southeast Asia and in eastern Indonesia and that gametocytogenesis might be easily switched on in Indonesian isolates. In wild isolates of P. vivax, P. malariae and P. ovale preserved for 2-9 days, ring forms or young trophozoites survived, but adaptation to in vitro culture failed. These results indicate that wild isolates can be preserved in wet ice for 9-10 days.
- Real-time PCR: Benefits for Detection of Mild and Asymptomatic Giardia Infections. [Journal Article]
- Trop Med Health 2012 Jun; 40(2):31-5.
The majority of Giardia infections are transmitted by the fecal-oral route and cause giardiasis. Children who live in crowded conditions or low socio-economic areas are the risk group for Giardia infection. Interestingly, most of them are asymptomatic or only mildly infected and can shed the Giardia cysts in the environment. Thus, the diagnosis of Giardia infection in asymptomatic or mild infection plays an important role in achieving control of Giardia duodenalis transmission. The objective of this study was to examine parasitic infections using microscopy and to develop a real-time PCR method for detection of Giardia infection in the stool samples of children living on the Thai-Myanmar border. Both species-specific primers and fluorescent labeled G. duodenalis probe were designed using small-subunit ribosomal RNA (ssrRNA). The results showed that 10 (7.69%) and 40 (30.77%) of 130 stool samples were positive for G. duodenalis by microscopy and real-time PCR respectively. Only 3 out of 9 liquid stools revealed G. duodenalis positive using microscopy, but all of them were G. duodenalis-positive using real-time PCR. The detection limit of real-time PCR for G. duodenalis was 0.1 pg/25 µl reaction. It can detect both mild and asymptomatic Giardia infections in children living on the Thai-Myanmar border.