Tropical medicine is the branch of medicine that deals with health problems that either occur uniquely in tropical and subtropical regions or are either more widespread in the tropics or more difficult to prevent or control.

Many infections that are classified as "tropical diseases" used to be endemic in countries located in temperate or even cold areas. That was the case for leprosy, cholera, malaria, hookworm infestations, amoebiasis, among others. The disappearance of those diseases from developed countries was primarily caused by improvements in housing, diet, sanitation, and personal hygiene. Since climate is not the main reason why those infections remain endemic in tropical areas, there is a trend towards renaming this speciality as "Geographic Medicine".

See also

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• Tropical disease

Organizations

• The American Society of Tropical Medicine and Hygiene
• The Royal Society of Tropical Medicine and Hygiene

Medical specialties

More on [ Tropical medicine ]

pubmed: 0002-9637

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Zimic M, García HH, Gilman RH In response. Am J Trop Med Hyg. 2009 Dec;81(6):1166 Authors: Zimic M, García HH, Gilman RH PMID: 19996454 [PubMed - in process]
Diagnosis of Human Cysticercosis and Taenia asiatica.
Galan-Puchades MT, Fuentes MV Diagnosis of Human Cysticercosis and Taenia asiatica. Am J Trop Med Hyg. 2009 Dec;81(6):1165 Authors: Galan-Puchades MT, Fuentes MV PMID: 19996453 [PubMed - in process]
Experimental Infection of Cliff Swallows (Petrochelidon pyrrhonota) with Varying Doses of West Nile Virus.
Oesterle PT, Nemeth NM, Vandalen K, Sullivan H, Bentler KT, Young GR, McLean RG, Clark L, Smeraski C, Hall JS Experimental Infection of Cliff Swallows (Petrochelidon pyrrhonota) with Varying Doses of West Nile Virus. Am J Trop Med Hyg. 2009 Dec;81(6):1159-64 Authors: Oesterle PT, Nemeth NM, Vandalen K, Sullivan H, Bentler KT, Young GR, McLean RG, Clark L, Smeraski C, Hall JS Cliff swallows (Petrochelidon pyrrhonota) were inoculated with differing doses of West Nile virus (WNV) to evaluate their potential role as reservoir hosts in nature. Swallows often nest in large colonies in habitats and months associated with high mosquito abundance and early WNV transmission in North America. Additionally, cliff swallow diet consists of insects, including mosquitoes, leading to an additional potential route of WNV infection. The average peak viremia titer among infected cliff swallows was 10(6.3) plaque-forming units (PFU)/mL serum and the reservoir competence index was 0.34. There was no correlation between dose and probability of becoming infected or viremia peak and duration. Oral shedding was detected from 2 to 14 days post-inoculation with an average peak titer of 10(4.4) PFU/swab. These results suggest that cliff swallows are competent reservoir hosts of WNV and therefore, they may play a role in early seasonal amplification and maintenance of WNV. PMID: 19996452 [PubMed - in process]
Prevalence of West Nile Virus in Migratory Birds during Spring and Fall Migration.
Dusek RJ, McLean RG, Kramer LD, Ubico SR, Dupuis AP, Ebel GD, Guptill SC Prevalence of West Nile Virus in Migratory Birds during Spring and Fall Migration. Am J Trop Med Hyg. 2009 Dec;81(6):1151-8 Authors: Dusek RJ, McLean RG, Kramer LD, Ubico SR, Dupuis AP, Ebel GD, Guptill SC To investigate the role of migratory birds in the dissemination of West Nile virus (WNV), we measured the prevalence of infectious WNV and specific WNV neutralizing antibodies in birds, principally Passeriformes, during spring and fall migrations in the Atlantic and Mississippi flyways from 2001-2003. Blood samples were obtained from 13,403 birds, representing 133 species. Specific WNV neutralizing antibody was detected in 254 resident and migratory birds, representing 39 species, and was most commonly detected in northern cardinals (Cardinalis cardinalis) (9.8%, N = 762) and gray catbirds (Dumetella carolinensis) (3.2%, N = 3188). West Nile virus viremias were detected in 19 birds, including 8 gray catbirds, and only during the fall migratory period. These results provide additional evidence that migratory birds may have been a principal agent for the spread of WNV in North America and provide data on the occurrence of WNV in a variety of bird species. PMID: 19996451 [PubMed - in process]
Evaluation of IgM Antibody Capture Enzyme-Linked Immunosorbent Assay Kits for Detection of IgM against Japanese Encephalitis Virus in Cerebrospinal Fluid Samples.
Ravi V, Robinson JS, Russell BJ, Desai A, Ramamurty N, Featherstone D, Johnson BW Evaluation of IgM Antibody Capture Enzyme-Linked Immunosorbent Assay Kits for Detection of IgM against Japanese Encephalitis Virus in Cerebrospinal Fluid Samples. Am J Trop Med Hyg. 2009 Dec;81(6):1144-50 Authors: Ravi V, Robinson JS, Russell BJ, Desai A, Ramamurty N, Featherstone D, Johnson BW Infection with Japanese encephalitis virus (JEV) is a major public health problem in Asia. Detection of JEV-specific IgM in serum and cerebrospinal fluid (CSF) by the IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) is currently the most widely used diagnostic method to detect JEV infection. Because of the possible presence of IgM cross-reactivity with other flaviviruses in serum and the high ratio of inapparent-to-apparent JEV infections, a positive result in serum only suggests a recent infection and not necessarily an encephalitic illness caused by JEV. Consequently, detection of JEV-specific IgM in CSF assumes great diagnostic relevance. We evaluated two commercial JEV MAC-ELISA kits using 60 CSF samples obtained from patients with acute encephalitis syndrome. The Panbio and XCyton kits had sensitivities of 65-80% and 95% and specificities of 90% and 97.5%, respectively. Performance information on these commercial JEV MAC-ELISA kits for CSF should assist in laboratory-based JE surveillance programs. PMID: 19996450 [PubMed - in process]
Incidence of yellow Fever vaccine-associated neurotropic disease.
Guimard T, Minjolle S, Polard E, Fily F, Zeller H, Michelet C, Tattevin P Incidence of yellow Fever vaccine-associated neurotropic disease. Am J Trop Med Hyg. 2009 Dec;81(6):1141-3 Authors: Guimard T, Minjolle S, Polard E, Fily F, Zeller H, Michelet C, Tattevin P Although the yellow fever 17D strain live-attenuated vaccine has been widely used over the past seven decades with a long history of safe records, recent reports of serious, sometimes fatal, adverse events, raised concerns about its tolerance. We extracted all cases of serious neurologic adverse events that occurred within 30 days of yellow fever vaccination in our institution during 2000-2008. Four cases (meningitis, n = 2 and meningo-encephalitis, n = 2) were identified. The male:female ratio was 3:1, and ages ranged from 21 to 55 years. Cerebrospinal fluid examination showed pleocytosis (10-82 cells/mm(3), 64-84% lymphocytes), with slightly elevated protein levels (0.4-0.68 g/L). All symptoms resolved in three patients, but attention disorder and cerebellar syndrome persisted in one patient (at six months follow-up). The incidence of yellow fever vaccine-associated serious neurologic events was estimated to be 9.9/100,000 vaccine doses (95% confidence interval = 2.7-25.4/100,000) in this study, which was 10 times higher than previous estimates that did not include acute meningitis. PMID: 19996449 [PubMed - in process]
Emergence of tick-borne granulocytic anaplasmosis associated with habitat type and forest change in northern california.
Foley JE, Nieto NC, Foley P Emergence of tick-borne granulocytic anaplasmosis associated with habitat type and forest change in northern california. Am J Trop Med Hyg. 2009 Dec;81(6):1132-40 Authors: Foley JE, Nieto NC, Foley P An important ecosystem service of intact forests is protection from some emerging infectious diseases. Tick-transmitted disease granulocytic anaplasmosis increasingly occupies second-growth forest. We hypothesized that areas of second growth would have increases in tick and rodent abundance, facilitating emergence of anaplasmosis. We predicted Anaplasma phagocytophilum presence as a function of biocomplexity and forest structure, including vegetation, ticks, and rodents in four sites in California. Significant risk factors for exposure included host species (woodrats with 13% seroprevalence, odds ratio [OR] = 8.3 and chipmunks with 27% seroprevalence, OR = 20.7), and park location (northern parks, OR 25.5-27.7). Exposure to A. phagocytophilum was more likely among chipmunks in redwood sites at one park, but with woodrats and oaks at another. Overall, transects on which small mammals showed greatest A. phagocytophilum exposure had high biodiversity in ticks, rodents, and vegetation, as well as intermediate-sized trees with a high mean and variance in diameter at breast height, findings which suggest that a dilution effect, where increased biodiversity reduces disease risk, does not necessarily apply in this system. Thus, enzootic and potentially emerging anaplasmosis were linked to high biodiversity and mature second-growth forest. PMID: 19996448 [PubMed - in process]
Niche partitioning of Borrelia burgdorferi and Borrelia miyamotoi in the same tick vector and mammalian reservoir species.
Barbour AG, Bunikis J, Travinsky B, Hoen AG, Diuk-Wasser MA, Fish D, Tsao JI Niche partitioning of Borrelia burgdorferi and Borrelia miyamotoi in the same tick vector and mammalian reservoir species. Am J Trop Med Hyg. 2009 Dec;81(6):1120-31 Authors: Barbour AG, Bunikis J, Travinsky B, Hoen AG, Diuk-Wasser MA, Fish D, Tsao JI The Lyme borreliosis agent Borrelia burgdorferi and the relapsing fever group species Borrelia miyamotoi co-occur in the United States. We used species-specific, quantitative polymerase chain reaction to study both species in the blood and skin of Peromyscus leucopus mice and host-seeking Ixodes scapularis nymphs at a Connecticut site. Bacteremias with B. burgdorferi or B. miyamotoi were most prevalent during periods of greatest activity for nymphs or larvae, respectively. Whereas B. burgdorferi was 30-fold more frequent than B. miyamotoi in skin biopsies and mice had higher densities of B. burgdorferi densities in the skin than in the blood, B. miyamotoi densities were higher in blood than skin. In a survey of host-seeking nymphs in 11 northern states, infection prevalences for B. burgdorferi and B. miyamotoi averaged approximately 0.20 and approximately 0.02, respectively. Co-infections of P. leucopus or I. scapularis with both B. burgdorferi and B. miyamotoi were neither more nor less common than random expectations. PMID: 19996447 [PubMed - in process]
Baseline iron indices as predictors of hemoglobin improvement in anemic Vietnamese women receiving weekly iron-folic acid supplementation and deworming.
Pasricha SR, Casey GJ, Phuc TQ, Mihrshahi S, MacGregor L, Montresor A, Tien N, Biggs BA Baseline iron indices as predictors of hemoglobin improvement in anemic Vietnamese women receiving weekly iron-folic acid supplementation and deworming. Am J Trop Med Hyg. 2009 Dec;81(6):1114-9 Authors: Pasricha SR, Casey GJ, Phuc TQ, Mihrshahi S, MacGregor L, Montresor A, Tien N, Biggs BA Iron deficiency anemia is highly prevalent among women living in rural Vietnam. However, the utility and cut-offs of indices for diagnosing iron deficiency anemia in the public health context is ill defined. We assessed the ability of iron indices to predict the hemoglobin response (HBR) to weekly iron-folic acid supplementation (WIFS) in anemic rural Vietnamese women. We compared hemoglobin, serum ferritin, and soluble transferrin receptor in a cohort of 221 non-pregnant women of reproductive age before and after 3 months of WIFS and deworming. At baseline, anemia (Hb < 120 g/L) was present in 81/221 (36.7%) of subjects. After 3 months, anemia prevalence fell to 58/221 (26.2%), and the mean hemoglobin change was +3.5 g/L (95% confidence interval, 0.9, 6.6). A hemoglobin response was observed in 50/75 (66.6%) of anemic women. A ferritin cut-off < 30 ng/mL was a more sensitive predictor of response than ferritin < 15 ng/mL. PMID: 19996446 [PubMed - in process]

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