PURPOSE: To review the clinical features and natural courses of cold urticaria (ColdU) in a tropical country. METHODS: A retrospective chart review was performed of patients who visited Siriraj Urticaria Clinic, Siriraj Hospital, Bangkok, Thailand, and were diagnosed with ColdU between 2007 and 2018. Data on provocation and threshold tests, clinical courses, and laboratory work-up were analyzed and compared with data reported by studies in temperate countries. RESULTS: Of 1,063 chronic urticaria patients, 27 (2.5%) were diagnosed with ColdU, with a mean age of symptom onset of 34.8 years. Half of the patients had a history of atopy, and 1 (3.7%) had a history of anaphylaxis. All patients were positive to 1 of 3 provocation tests: an ice cube test; TempTest 4.0; or a tray filled with ice, salt and water. Thirteen patients underwent the ice cube test, and all had positive results. TempTest was performed on 15 patients, 8 of whom had positive results, with a mean critical temperature threshold (CTT) of 21.0°C. All of the 7 patients who had a negative TempTest result later produced positive results to the immersion of their hand and forearm in a tray filled with ice, salt, and water. All patients were treated with H1-antihistamines, the vast majority (96.3%) being non-sedating H1-antihistamines. Some (14.8%) needed to be administered oral corticosteroids, ciclosporin, or omalizumab. Six patients (22.2%) were in remission. A Kaplan-Meier survival curve demonstrated 5-year and 10-year remission rates of 13.8% and 42.6%, respectively. CONCLUSIONS: The rate of anaphylaxis in patients with ColdU in a tropical country was lower than those reported by other studies conducted intemperate climates. On the other hand, the number of female patients, mean age at symptom onset, atopy rate, rate of concomitant chronic spontaneous urticaria and mean CTT were higher.
Adrenal Cortex Hormones ; Anaphylaxis ; Climate ; Cyclosporine ; Female ; Forearm ; Hand ; Humans ; Ice ; Immersion ; Omalizumab ; Retrospective Studies ; Thailand ; Tropical Climate ; Urticaria ; Water

The present study describes the genotypic distribution of rotaviruses (RVs) in an Indian bovine population with unexpectedly higher proportions of G3 alone or in combination of G8/G10. PCR-genotyping confirmed that 39.4% (13/33) of the prevalent RVs were the G3 type while 60.6% (20/33) were dual G3G10 or G3G8 types. P typing revealed that 93.9% (31/33) of the samples were P[11] while 6.1% (2/33) possessed a dual P[1]P[11] type. Sequence analysis of the VP7 gene from G3 strains viz. B-46, 0970, and BR-133 showed that these strains had sequence identities of 90.5% to 100% with other bovine G3 strains. The highest identity (98.9% to 100%) was observed with RUBV3 bovine G3 strains from eastern India. The G3 strains (B-46, 0970, and BR-133) showed 97.5% to 98.8% sequence homologies with the Indian equine RV strain Erv-80. Phylogenetic analysis demonstrated that G3 strains clustered with bovine RUBV3 and J-63, and equine Erv-80 G3. Overall, these results confirmed that the incidence of infection by RVs with the G3 genotype and mixed genotypes in the bovine population was higher than previously predicted. This finding reinforces the importance of constantly monitoring circulating viral strains with the G3 genotype in future surveillance studies.
Animals ; Cattle ; Cattle Diseases/epidemiology/*virology ; Desert Climate ; Feces/virology ; Genotype ; India/epidemiology ; Molecular Sequence Data ; Phylogeny ; RNA, Viral/genetics ; Reverse Transcriptase Polymerase Chain Reaction/veterinary ; Rotavirus/classification/*genetics/isolation & purification ; Rotavirus Infections/epidemiology/*veterinary/virology ; Sequence Analysis, Protein/veterinary ; Sequence Analysis, RNA/veterinary ; Sequence Homology ; Tropical Climate

Tropical inhabitants are able to tolerate heat through permanent residence in hot and often humid tropical climates. The goal of this study was to clarify the peripheral mechanisms involved in thermal sweating pre and post exposure (heat-acclimatization over 10 days) by studying the sweating responses to acetylcholine (ACh), a primary neurotransmitter of sudomotor activity, in healthy subjects (n=12). Ten percent ACh was administered on the inner forearm skin for iontophoresis. Quantitative sudomotor axon reflex testing, after iontophoresis (2 mA for 5 min) with ACH, was performed to determine directly activated (DIR) and axon reflex-mediated (AXR) sweating during ACh iontophoresis. The sweat rate, activated sweat gland density, sweat gland output per single gland activated, as well as oral and skin temperature changes were measured. The post exposure activity had a short onset time (p<0.01), higher active sweat rate [(AXR (p<0.001) and DIR (p<0.001)], higher sweat output per gland (p<0.001) and higher transepidermal water loss (p<0.001) compared to the pre-exposure measurements. The activated sweat rate in the sudomotor activity increased the output for post-exposure compared to the pre-exposure measurements. The results suggested that post-exposure activity showed a higher active sweat gland output due to the combination of a higher AXR (DIR) sweat rate and a shorter onset time. Therefore, higher sudomotor responses to ACh receptors indicate accelerated sympathetic nerve responsiveness to ACh sensitivity by exposure to environmental conditions.
Acetylcholine ; Axons ; Forearm ; Hot Temperature ; Iontophoresis ; Neurotransmitter Agents ; Receptors, Cholinergic ; Reflex ; Skin ; Skin Temperature ; Sweat ; Sweat Glands ; Sweating ; Tropical Climate

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.
Animals ; Communicable Diseases/*genetics/*parasitology ; Helminths/*genetics/metabolism ; Humans ; Insect Vectors/*genetics/metabolism ; Protozoa/*genetics/physiology ; *RNA Interference ; *Tropical Climate

Introduction of double-stranded RNA (dsRNA) into some cells or organisms results in degradation of its homologous mRNA, a process called RNA interference (RNAi). The dsRNAs are processed into short interfering RNAs (siRNAs) that subsequently bind to the RNA-induced silencing complex (RISC), causing degradation of target mRNAs. Because of this sequence-specific ability to silence target genes, RNAi has been extensively used to study gene functions and has the potential to control disease pathogens or vectors. With this promise of RNAi to control pathogens and vectors, this paper reviews the current status of RNAi in protozoans, animal parasitic helminths and disease-transmitting vectors, such as insects. Many pathogens and vectors cause severe parasitic diseases in tropical regions and it is difficult to control once the host has been invaded. Intracellularly, RNAi can be highly effective in impeding parasitic development and proliferation within the host. To fully realize its potential as a means to control tropical diseases, appropriate delivery methods for RNAi should be developed, and possible off-target effects should be minimized for specific gene suppression. RNAi can also be utilized to reduce vector competence to interfere with disease transmission, as genes critical for pathogenesis of tropical diseases are knockdowned via RNAi.
Animals ; Communicable Diseases/*genetics/*parasitology ; Helminths/*genetics/metabolism ; Humans ; Insect Vectors/*genetics/metabolism ; Protozoa/*genetics/physiology ; *RNA Interference ; *Tropical Climate

INTRODUCTIONInfluenza vaccine has been shown to be highly effective in temperate regions with well-defined seasonal influenza. Healthcare workers (HCWs) are advised to receive regular influenza vaccination to protect themselves and their patients. However, there are limited data on the efficacy of influenza vaccine in HCWs in the tropics.

MATERIALS AND METHODSIn this observational, investigator blinded cohort study, bi-monthly questionnaires recording influenza-like illness (ILI) episodes and medical leave were administered to 541 HCWs at the Singapore National University Hospital and KK Women's and Children's Hospital from 2004 to 2005. ILI was defined according to a standard symptom score.

RESULTSBaseline characteristics were comparable in both the vaccinated and non-vaccinated groups. Overall, the relative risk of self-reported ILI in vaccinated HCWs was 1.13 [95% confidence interval (CI), 0.98-1.13; P=0.107]; medical leave taken was lower in the vaccinated group [mean 0.26+/-0.6 days per visit, compared with 0.30+/-0.5 days in the non-vaccinated group (P=0.40)]. Because of the reported Northern Hemisphere 2003/04 vaccine mismatch, we stratified the cohort and determined that the group which received a matched vaccine had a relative risk of ILI of 0.49 (95% CI, 0.37-0.66; P<0.001), achieving a vaccine efficacy of 51%. Mean medical leave decreased significantly in HCWs who received the matched vaccine, compared with those who did not receive vaccination (0.13+/-0.3 vs 0.30+/-0.5; P<0.001) and with HCWs vaccinated with mismatched strains (0.13+/-0.3 vs 0.39+/-0.9; P=0.01).

CONCLUSIONSA well-matched influenza vaccine is effective in preventing ILI and reducing sickness absence in healthcare workers in tropical settings. Efforts need to be made to increase influenza vaccination rates and to improve the currently available vaccines.

Adult ; Attitude of Health Personnel ; Cohort Studies ; Confidence Intervals ; Female ; Health Personnel ; statistics & numerical data ; Humans ; Influenza Vaccines ; Influenza, Human ; epidemiology ; prevention & control ; Male ; Occupational Exposure ; Occupational Health ; Prospective Studies ; Risk ; Singapore ; epidemiology ; Single-Blind Method ; Surveys and Questionnaires ; Tropical Climate

Paederus dermatitis is a characteristic irritant contact dermatitis caused by paederin which is a chemical substance released by insects of the genus Paederus. Erythematous vesiculobullous eruption with a burning sensation occur within 24 hours after contact with Paederus. This dermatitis is frequently seen in regions with hot, tropical climates such as Africa and the Middle East. There have been a few reports of Paederus dermatitis in Korea. We recently had a patient with Paederus dermatitis who traveled to Kenya. We would like to highlight an awareness of this peculiar dermatitis due to the increasing numbers of travelers visiting tropical countries.
Africa ; Burns ; Dermatitis* ; Dermatitis, Contact ; Humans ; Insects ; Kenya ; Korea ; Middle East ; Sensation ; Tropical Climate

OBJECTIVETo investigate the bacterial flora and their drug resistance in hospitalized burn patients on tropical islands.

METHODSRetrospective study was carried out to analyze pathogenic microorganisms and their drug resistance characteristics in 392 burn patients hospitalized during 2000-2005.

RESULTS(1) Totally 671 strains of bacteria were isolated, among which Pseudomonas aeruginosa, Staphylococcus aureus, Aerobacter cloacae and Acinetobacter species were predominant, but the isolation rate of Pseudomonas aeruginosa was declining compared with that in 1990's. (2) The resistance rate of Pseudomonas aeruginosa to imipenem and cefepime was 32.2% and 36.7% , respectively, while that to other antibiotics was above 80%. (3) Among 141 strains of Staphylococcus aureus, 89 strains (63.1%) of MRSA were isolated, and none of them were resistant to Vancomycin.

CONCLUSIONPseudomonas aeruginosa, Staphylococcus aureus, Aerobacter cloacae and Acinetobacter species were predominant in tropical islands. The species of the pathogens are changing . The drug resistance rates of Pseudomonas aeruginosa and Staphylococcus aureus are rather high.

Adolescent ; Adult ; Aged ; Anti-Bacterial Agents ; pharmacology ; Burns ; drug therapy ; microbiology ; Child ; Child, Preschool ; Drug Resistance, Bacterial ; Female ; Humans ; Infant ; Male ; Microbial Sensitivity Tests ; Middle Aged ; Pseudomonas aeruginosa ; drug effects ; isolation & purification ; Retrospective Studies ; Staphylococcus aureus ; drug effects ; isolation & purification ; Tropical Climate ; Young Adult

Representative pioneer tree root systems in the subtropical area of South China were examined with regard to their structure, underground stratification and biomass distribution. Excavation of skeleton roots and observation of fine roots of seven species including the Euphorbiaceae, Theaceae, Melastomataceae, Lauraceae and Fagaceae families was carried out. The results showed that: (1) Pioneer tree roots in the first stage of natural succession were of two types, one characterized by taproot system with bulky plagiotropic branches; the other characterized by flat root system with several tabular roots. The late mesophilous tree roots were characterized by one obvious taproot and tactic braches roots up and down. Shrub species roots were characterized by heart fibrous root type featured both by horizontally and transversally growing branches. Root shapes varied in different dominant species at different stages of succession. (2) Roots of the different species varied in the external features-color, periderm and structure of freshly cut slash. (3) In a set of successional stages the biomass of tree roots increased linearly with the age of growth. During monsoon, the total root biomass amounted to 115.70 t/ha in the evergreen broad-leaved forest; 50.61 t/ha in needle and broad-leaved mixed forest dominated by coniferous forest; and 64.20 t/ha in broad-and needle-leaved mixed forest dominated by broad-leaved heliophytes, and are comparable to the underground biomass observed in similar tropical forests. This is the first report about roots characteristics of forest in the lower sub-tropical area of Dinghushan, Guangdong, China.
Biomass ; China ; Magnoliopsida ; growth & development ; Plant Roots ; growth & development ; Time Factors ; Trees ; growth & development ; Tropical Climate

Dengue fever is caused by the dengue virus which belongs to the flaviviridae family and is transmitted by mosquitos. It occurs in the tropical climates of central and south america, asia, and africa and is considered one of the most important arthropod-borne viral diseases as regards morbidity and mortality, especially due to its hemorrhagic forms, dengue hemorrhagic fever and dengue shock syndrome. We report a case of dengue fever which presented with typical systemic symptoms and signs such as fever, headache, nausea and characteristic erythroderma (white islands in a sea of red) on travelling Bangladesh.
Africa ; Asia ; Bangladesh ; Culicidae ; Dengue Virus ; Dengue* ; Dermatitis, Exfoliative ; Fever ; Flaviviridae ; Headache ; Humans ; Islands ; Mortality ; Nausea ; Severe Dengue ; South America ; Tropical Climate ; Virus Diseases