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 ]

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Lack of Evidence of Hepatitis C and HIV Co-Infection among Men Who Have Sex with Men in Peru.
Lama JR, Lucchetti A, Cabezas C, Suarez-Ognio L, Related Articles Lack of Evidence of Hepatitis C and HIV Co-Infection among Men Who Have Sex with Men in Peru. Am J Trop Med Hyg. 2009 Jul;81(1):184-6 Authors: Lama JR, Lucchetti A, Cabezas C, Suarez-Ognio L, Hepatitis C virus (HCV) infection occurs among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM) because of shared routes of transmission. To assess the association between HCV and HIV infection among MSM in Peru, we conducted a matched case-control study (162 HIV-positive cases and 324 HIV-negative controls) among participants of an HIV sentinel surveillance survey in six urban cities. The HCV infection was initially screened using anti-HCV ELISA and immunoblot assay, and thereafter confirmed by the HCV RNA qualitative assay. Among cases, no confirmed HCV infection was found while among controls, only two confirmed HCV infections were reported (0.62%). This matched case-control reports a very low probability of association between HCV and HIV co-infection and suggests a very low prevalence of HCV infection among MSM in Peru. PMID: 19556587 [PubMed - in process]
Seasonality of influenza in the tropics: a distinct pattern in northeastern Brazil.
Moura FE, Perdigão AC, Siqueira MM Related Articles Seasonality of influenza in the tropics: a distinct pattern in northeastern Brazil. Am J Trop Med Hyg. 2009 Jul;81(1):180-3 Authors: Moura FE, Perdigão AC, Siqueira MM Influenza epidemics occur worldwide annually. The incidence of influenza shows a seasonal pattern in temperate areas, but little is known about influenza seasonality in tropical regions. The objective of this study was to determine the prevalence and the seasonal pattern of influenza infections in children living in the city of Fortaleza in northeastern Brazil. An indirect immunofluorescence assay was performed on nasopharyngeal aspirates collected from children attending in ambulatories, emergency rooms, and wards of the Hospital Infantil Albert Sabin with suspicion of acute respiratory infection during 7 consecutive years (2001-2007). Influenza viruses were detected in 6.3% (234/3,708) of specimens. Laboratory-based surveillance data showed a clear annual epidemic cycle of influenza, with a peak usually occurring in the rainy periods. In Fortaleza, flu infections occurred at a low level throughout the year but exhibit a marked seasonal increase during the rainy season. PMID: 19556586 [PubMed - in process]
Changes in West Nile Virus Seroprevalence and Antibody Titers among Wisconsin Mesopredators 2003-2006.
Docherty DE, Samuel MD, Egstad KF, Griffin KM, Nolden CA, Karwal L, Ip HS Related Articles Changes in West Nile Virus Seroprevalence and Antibody Titers among Wisconsin Mesopredators 2003-2006. Am J Trop Med Hyg. 2009 Jul;81(1):177-9 Authors: Docherty DE, Samuel MD, Egstad KF, Griffin KM, Nolden CA, Karwal L, Ip HS After the 2001 occurrence of West Nile virus (WNV) in Wisconsin (WI), we collected sera, during 2003-2006, from south-central WI mesopredators. We tested these sera to determine WNV antibody prevalence and geometric mean antibody titer (GMAT). Four-fold higher antibody prevalence and 2-fold higher GMAT in 2003-2004 indicated greater exposure of mesopredators to WNV during the apparent epizootic phase. The period 2005-2006 was likely the enzootic phase because WNV antibody prevalence fell to a level similar to other flaviviruses. Our results suggest that, in mesopredators, vector-borne transmission is the primary route of infection and WNV antibodies persist for < 1 year. Mesopredators may be sensitive indicators of West Nile virus spill-over into humans and horses. Mesopredator sero-surveys may complement dead crow surveillance by providing additional data for the timing of public health interventions. Research is needed to clarify the dynamics of WNV infection in these mammals and their role as potential WNV amplifiers. PMID: 19556585 [PubMed - in process]
A Community-based Survey of Human Toxoplasmosis in Rural Amazonia: Seroprevalence, Seroconversion Rate, and Associated Risk Factors.
Ferreira MU, Hiramoto RM, Aureliano DP, da Silva-Nunes M, da Silva NS, Malafronte RS, Muniz PT Related Articles A Community-based Survey of Human Toxoplasmosis in Rural Amazonia: Seroprevalence, Seroconversion Rate, and Associated Risk Factors. Am J Trop Med Hyg. 2009 Jul;81(1):171-176 Authors: Ferreira MU, Hiramoto RM, Aureliano DP, da Silva-Nunes M, da Silva NS, Malafronte RS, Muniz PT IgG antibodies to Toxoplasma gondii were detected in, March-April 2004, in 65.8% (95% confidence interval, 60.8-70.8%) of 342 systematically sampled subjects 5-90 years of age (87.5% of the eligible) living in a rural settlement in Amazonia, with a seroconversion rate of 9% over 1 year of follow-up of 99 seronegative subjects. Multiple logistic regression analysis identified age as the only significant independent predictor of seropositivity at the baseline. Each additional year of age increases the odds of being seropositive by 6%, and 76.8% of the subjects are expected to be seropositive at 30 years of age. A single high-prevalence spatial cluster, comprising 11.9% of the seropositive subjects, was detected in the area; households in the cluster were less likely to have dogs as pets and their heads had a lower education level, when compared with households located outside the cluster. The challenges for preventing human toxoplasmosis in tropical rural settings are discussed. PMID: 19556584 [PubMed - as supplied by publisher]
Dose-Response Assay Templates for In vitro Assessment of Resistance to Benzimidazole and Nicotinic Acetylcholine Receptor Agonist Drugs in Human Hookworms.
Kotze AC, Lowe A, O'Grady J, Kopp SR, Behnke JM Related Articles Dose-Response Assay Templates for In vitro Assessment of Resistance to Benzimidazole and Nicotinic Acetylcholine Receptor Agonist Drugs in Human Hookworms. Am J Trop Med Hyg. 2009 Jul;81(1):163-70 Authors: Kotze AC, Lowe A, O'Grady J, Kopp SR, Behnke JM With the implementation of mass drug administration programs for the control of human hookworms, there is a need to monitor for the emergence of drug resistance. We have therefore examined in vitro assays for monitoring sensitivity to benzimidazoles (egg hatch assay) and nicotinic acetylcholine receptor agonist drugs (motility and morphology assays), with a view to developing tools for monitoring drug sensitivity in the field. We have performed assays with Necator americanus and Ancylostoma ceylanicum, and combined this with published data on N. americanus and Ancylostoma caninum, to indicate the breadth of the responses of various hookworm species and isolates in these in vitro assays. This has allowed us to generate assay templates covering the known range of responses, with scope to cover any shift in response that may be indicative of resistance. These assays will have immediate applicability in monitoring for the emergence of drug resistance in human hookworm populations. PMID: 19556583 [PubMed - in process]
MM3-ELISA Detection of Fasciola hepatica Coproantigens in Preserved Human Stool Samples.
Ubeira FM, Muiño L, Valero MA, Periago MV, Pérez-Crespo I, Mezo M, González-Warleta M, Romarís F, Paniagua E, Cortizo S, Llovo J, Más-Coma S Related Articles MM3-ELISA Detection of Fasciola hepatica Coproantigens in Preserved Human Stool Samples. Am J Trop Med Hyg. 2009 Jul;81(1):156-162 Authors: Ubeira FM, Muiño L, Valero MA, Periago MV, Pérez-Crespo I, Mezo M, González-Warleta M, Romarís F, Paniagua E, Cortizo S, Llovo J, Más-Coma S In this study, we evaluate the MM3-COPRO method for detection of Fasciola coproantigens in human fecal samples, and the usefulness of a new preservative/diluent, CoproGuard, developed for preservation of Fasciola coproantigens. The MM3-COPRO assay was evaluated with 213 samples from healthy patients, 30 Fasciola positive fecal samples (according to the Kato-Katz method), and 83 samples from patients with other parasitic infections. All Fasciola positive specimens were detected with the MM3-COPRO assay (100% sensitivity) and there was no cross-reactivity with other common parasites present in the clinical specimens analyzed (100% specificity). The use of CoproGuard enhanced coproantigen extraction without affecting the detection limit of the assay, and the antigenicity of Fasciola coproantigens in fecal samples stored at 37 degrees C was retained throughout the entire observation period (120 days). We concluded that the MM3-COPRO ELISA combined with the use of CoproGuard may be a very useful tool for the diagnosis of human fascioliasis. PMID: 19556582 [PubMed - as supplied by publisher]
Incidence and Risk Factors of Opisthorchis viverrini Infections in a Rural Community in Thailand.
Rangsin R, Mungthin M, Taamasri P, Mongklon S, Aimpun P, Naaglor T, Leelayoova S Related Articles Incidence and Risk Factors of Opisthorchis viverrini Infections in a Rural Community in Thailand. Am J Trop Med Hyg. 2009 Jul;81(1):152-5 Authors: Rangsin R, Mungthin M, Taamasri P, Mongklon S, Aimpun P, Naaglor T, Leelayoova S Opisthorchis viverrini infection is one of the major public health problems in Thailand. Although information about transmission of this parasite to humans is well established, infections are still prevalent in the northern and northeastern Thailand. Thus, prospective epidemiologic information is needed for developing more effective public health interventions. A cohort study to identify incidence and risk factors of O. viverrini infection was conducted in a rural community in Thailand during December 2002-February 2004. The incidence rate of opisthorchiasis was 21.6/100 person-years. The independent factors associated with opisthorchiasis were an age > 60 years and consuming chopped raw fish salad (Koi pla). Thus, avoiding this raw fish salad should be emphasized in the national control program. PMID: 19556581 [PubMed - in process]
Etiology of Acute Undifferentiated Febrile Illness in the Amazon Basin of Ecuador.
Manock SR, Jacobsen KH, de Bravo NB, Russell KL, Negrete M, Olson JG, Sanchez JL, Blair PJ, Smalligan RD, Quist BK, Espín JF, Espinoza WR, Maccormick F, Fleming LC, Kochel T Related Articles Etiology of Acute Undifferentiated Febrile Illness in the Amazon Basin of Ecuador. Am J Trop Med Hyg. 2009 Jul;81(1):146-151 Authors: Manock SR, Jacobsen KH, de Bravo NB, Russell KL, Negrete M, Olson JG, Sanchez JL, Blair PJ, Smalligan RD, Quist BK, Espín JF, Espinoza WR, Maccormick F, Fleming LC, Kochel T We conducted a longitudinal observational study of 533 patients presenting to two hospitals in the Ecuadorean Amazon basin with acute undifferentiated febrile illness (AUFI) from 2001 through 2004. Viral isolation, reverse transcription-polymerase chain reaction (RT-PCR), IgM seroconversion, and malaria smears identified pathogens responsible for fever in 122 (40.1%) of 304 patients who provided both acute and convalescent blood samples. Leptospirosis was found in 40 (13.2%), malaria in 38 (12.5%), rickettsioses in 18 (5.9%), dengue fever in 16 (5.3%), Q fever in 15 (4.9%), brucellosis in 4 (1.3%), Ilhéus infection in 3 (1.0%), and Venezuelan equine encephalitis (VEE), Oropouche, and St. Louis encephalitis virus infections in less than 1% of these patients. Viral isolation and RT-PCR on another 229 participants who provided only acute samples identified 3 cases of dengue fever, 2 of VEE, and 1 of Ilhéus. None of these pathogens, except for malaria, had previously been detected in the study area. PMID: 19556580 [PubMed - as supplied by publisher]
Difficulties in Maintaining Improved Handwashing Behavior, Karachi, Pakistan.
Luby SP, Agboatwalla M, Bowen A, Kenah E, Sharker Y, Hoekstra RM Related Articles Difficulties in Maintaining Improved Handwashing Behavior, Karachi, Pakistan. Am J Trop Med Hyg. 2009 Jul;81(1):140-145 Authors: Luby SP, Agboatwalla M, Bowen A, Kenah E, Sharker Y, Hoekstra RM In an earlier study in Karachi, Pakistan, households that received free soap and handwashing promotion for 9 months reported 53% less diarrhea than controls. Eighteen months after the intervention ended, these households were enrolled in a follow-up study to assess sustainability of handwashing behavior. Upon re-enrollment, mothers in households originally assigned to the intervention were 1.5 times more likely to have a place with soap and water to wash hands (79% versus 53%, P = 0.001) and when asked to wash hands were 2.2 times more likely to rub their hands together at least three times (50% versus 23%, P = 0.002) compared with controls. In the ensuing 14 months, former intervention households reported a similar proportion of person-days with diarrhea (1.59% versus 1.88%, P = 0.66) as controls. Although intervention households showed better handwashing technique after 2 years without intervention, their soap purchases and diarrhea experience was not significantly different from controls. PMID: 19556579 [PubMed - as supplied by publisher]

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