• Breast Tuberculosis in Women: A Systematic Review

      Quaglio, G; Pizzol, D; Isaakidis, P; Bortolani, A; Tognon, F; Marotta, C; Di Gennaro, F; Putoto, G; Olliaro, P (American Society of Tropical Medicine and Hygiene, 2019-05-20)
      Breast tuberculosis (TB) is rarely reported and poorly described. This review aims to update the existing literature on risk factors, clinical presentations, constitutional symptoms, diagnostic procedures, and medical and surgical treatments for breast TB. In all, 1,478 cases of breast TB were collected. Previous history of TB was reported in 19% of cases. The most common clinical appearance of the lesion was breast lump (75%). The most common associated finding was axillary lymphadenitis (33%) followed by sinus or fistula (24%). The most common symptoms were pain and fever, reported in 42% and 28% of cases, respectively. The most used diagnostic method was fine-needle aspiration cytology (32%), followed by biopsy (27%), acid-fast bacteria Ziehl–Neelsen stain (26%), culture (13%), and polymerase chain reaction (2%). These tested positive in 64%, 93%, 27%, 26%, and 58% of cases, respectively. The majority (69%) of patients received a 6-month anti-TB treatment (isoniazid, rifampicin, pyrazinamide, and ethambutol). Surgery consisted of excision in 39% of cases, drainage in 23%, and mastectomy in 5%. The great majority of patients had a positive outcome. It often mimics breast cancer, which makes it difficult to diagnose. Most patients, when diagnosed in time, respond to antitubercular therapy alone.
    • Changes in Health-Seeking Behavior Did Not Result in Increased All-Cause Mortality During the Ebola Outbreak in Western Area, Sierra Leone

      Vygen, S; Tiffany, A; Rull, M; Ventura, A; Wolz, A; Jambai, A; Porten, K (American Society of Tropical Medicine and Hygiene, 2016-07-25)
      Little is known about the residual effects of the west African Ebola virus disease (Ebola) epidemic on non-Ebola mortality and health-seeking behavior in Sierra Leone. We conducted a retrospective household survey to estimate mortality and describe health-seeking behavior in Western Area, Sierra Leone, between May 25, 2014, and February 16, 2015. We used two-stage cluster sampling, selected 30 geographical sectors with probability proportional to population size, and sampled 30 households per sector. Survey teams conducted face-to-face interviews and collected information on mortality and health-seeking behavior. We calculated all-cause and Ebola-specific mortality rates and compared health-seeking behavior before and during the Ebola epidemic using χ(2) and Fisher's exact tests. Ninety-six deaths, 39 due to Ebola, were reported in 898 households. All-cause and Ebola-specific mortality rates were 0.52 (95% confidence interval [CI] = 0.29-0.76) and 0.19 (95% CI = 0.01-0.38) per 10,000 inhabitants per day, respectively. Of those households that reported a sick family member during the month before the survey, 86% (73/85) sought care at a health facility before the epidemic, compared with 58% (50/86) in February 2015 (P = 0.013). Reported self-medication increased from 4% (3/85) before the epidemic to 23% (20/86) during the epidemic (P = 0.013). Underutilization of health services and increased self-medication did not show a demonstrable effect on non-Ebola-related mortality. Nevertheless, the residual effects of outbreaks need to be taken into account for the future. Recovery efforts should focus on rebuilding both the formalized health system and the population's trust in it.
    • Development of a Prediction Model for Ebola Virus Disease: A Retrospective Study in Nzérékoré Ebola Treatment Center, Guinea

      Loubet, P; Palich, R; Kojan, R; Peyrouset, O; Danel, C; Nicholas, S; Conde, M; Porten, K; Augier, A; Yazdanpanah, Y (American Society of Tropical Medicine and Hygiene, 2016-12-07)
      The 2014 Ebola epidemic has shown the importance of accurate and rapid triage tools for patients with suspected Ebola virus disease (EVD). Our objective was to create a predictive score for EVD. We retrospectively reviewed all suspected cases admitted to the Ebola treatment center (ETC) in Nzérékoré, Guinea, between December 2, 2014, and February 23, 2015. We used a multivariate logistic regression model to identify clinical and epidemiological factors associated with EVD, which were used to create a predictive score. A bootstrap sampling method was applied to our sample to determine characteristics of the score to discriminate EVD. Among the 145 patients included in the study (48% male, median age 29 years), EVD was confirmed in 76 (52%) patients. One hundred and eleven (77%) patients had at least one epidemiological risk factor. Optimal cutoff value of fever to discriminate EVD was 38.5°C. After adjustment on presence of a risk factor, temperature higher than 38.5°C (odds ratio [OR] = 18.1, 95% confidence interval [CI] = 7.6-42.9), and anorexia (OR = 2.5, 95% CI = 1.1-6.1) were independently associated with EVD. The score had an area under curve of 0.85 (95% CI = 0.78-0.91) for the prediction of laboratory-confirmed EVD. Classification of patients in a high-risk group according to the score had a lower sensitivity (71% versus 86%) but higher specificity (85% versus 41%) than the existing World Health Organization algorithm. This score, which requires external validation, may be used in high-prevalence settings to identify different levels of risk in EVD suspected patients and thus allow a better orientation in different wards of ETC.
    • Electrocardiographic safety evaluation of dihydroartemisinin piperaquine in the treatment of uncomplicated falciparum malaria.

      Mytton, O T; Ashley, E A; Peto, L; Price, R N; La, Y; Hae, R; Singhasivanon, P; White, N J; Nosten, F; Shoklo Malaria Research Unit, Mae Sot, Thailand. (American Society of Tropical Medicine and Hygiene, 2007-09)
      Dihydroartemisinin-piperaquine (DP) could become a leading fixed combination malaria treatment worldwide. Although there is accumulating evidence of efficacy and safety from clinical trials, data on cardiotoxicity are limited. In two randomized controlled trials in Thailand, 56 patients had ECGs performed before treatment, 4 hours after the first dose, and 4 hours after the last dose. The mean (95% CI) changes in QTc interval (Bazett's correction) were 2 (-6 to 9) ms and 14 (7 to 21) ms, respectively. These small changes on the third day of treatment are similar to those observed elsewhere in the convalescent phase following antimalarial treatment with drugs known to have no cardiac effects and are therefore likely to result from recovery from acute malaria and not the treatment given. At therapeutic doses, DP does not have clinically significant effects on the electrocardiogram.
    • Emerging Filoviral Disease in Uganda: Proposed Explanations and Research Directions

      Polonsky, Jonathan A; Wamala, Joseph F; de Clerck, Hilde; Van Herp, Michel; Sprecher, Armand; Porten, Klaudia; Shoemaker, Trevor (American Society of Tropical Medicine and Hygiene, 2014-02-10)
      Outbreaks of Ebola and Marburg virus diseases have recently increased in frequency in Uganda. This increase is probably caused by a combination of improved surveillance and laboratory capacity, increased contact between humans and the natural reservoir of the viruses, and fluctuations in viral load and prevalence in this reservoir. The roles of these proposed explanations must be investigated to guide appropriate responses to the changing epidemiological profile. Other African settings in which multiple filoviral outbreaks have occurred could also benefit from such information.
    • Feasibility of Training Clinical Officers in Point-of-Care Ultrasound for Pediatric Respiratory Diseases in Aweil, South Sudan.

      Nadimpalli, A; Tsung, JW; Sanchez, R; Shah, S; Zelikova, E; Umphrey, L; Hurtado, N; Gonzalez, A; Teicher, C (American Society of Tropical Medicine and Hygiene, 2019-09-01)
      Lower respiratory tract infections (LRTIs) are the leading cause of deaths in children < 5 years old worldwide, particularly affecting low-resource settings such as Aweil, South Sudan. In these settings, diagnosis can be difficult because of either lack of access to radiography or clinical algorithms that overtreat children with antibiotics who only have viral LRTIs. Point-of-care ultrasound (POCUS) has been applied to LRTIs, but not by nonphysician clinicians, and with limited data from low-resource settings. Our goal was to examine the feasibility of training the mid-level provider cadre clinical officers (COs) in a Médecins Sans Frontières project in South Sudan to perform a POCUS algorithm to differentiate among causes of LRTI. Six COs underwent POCUS training, and each subsequently performed 60 lung POCUS studies on hospitalized pediatric patients < 5 years old with criteria for pneumonia. Two blinded experts, with a tiebreaker expert adjudicating discordant results, served as a reference standard to calculate test performance characteristics, assessed image quality and CO interpretation. The COs performed 360 studies. Reviewers rated 99.1% of the images acceptable and 86.0% CO interpretations appropriate. The inter-rater agreement (κ) between COs and experts for lung consolidation with air bronchograms was 0.73 (0.63-0.82) and for viral LRTI/bronchiolitis was 0.81 (0.74-0.87). It is feasible to train COs in South Sudan to use a POCUS algorithm to diagnose pneumonia and other pulmonary diseases in children < 5 years old.
    • High Hepatitis E Seroprevalence Among Displaced Persons in South Sudan

      Azman, A; Bouhenia, M; Iyer, A; Rumunu, J; Laku, R; Wamala, J; Rodriguez-Barraquer, I; Lessler, J; Gignoux, E; Luquero, F; et al. (American Society of Tropical Medicine and Hygiene, 2017-06)
      AbstractLarge protracted outbreaks of hepatitis E virus (HEV) have been documented in displaced populations in Africa over the past decade though data are limited outside these exceptional settings. Serological studies can provide insights useful for improving surveillance and disease control. We conducted an age-stratified serological survey using samples previously collected for another research study from 206 residents of an internally displaced person camp in Juba, South Sudan. We tested serum for anti-HEV antibodies (IgM and IgG) and estimated the prevalence of recent and historical exposure to the virus. Using data on individuals' serostatus, camp arrival date, and state of origin, we used catalytic transmission models to estimate the relative risk of HEV infection in the camp compared with that in the participants' home states. The age-adjusted seroprevalence of anti-HEV IgG was 71% (95% confidence interval = 63-78), and 4% had evidence of recent exposure (IgM). We estimated HEV exposure rates to be more than 2-fold (hazard ratio = 2.3, 95% credible interval = 0.3-5.8) higher in the camp than in the participants' home states, although this difference was not statistically significant. HEV transmission may be higher than previously appreciated, even in the absence of reported cases. Improved surveillance in similar settings is needed to understand the burden of disease and minimize epidemic impact through early detection and response.
    • High Prevalence of Shigella or Enteroinvasive Escherichia coli Carriage among Residents of an Internally Displaced Persons Camp in South Sudan

      Bliss, J; Bouhenia, M; Hale, P; Couturier, BA; Iyer, AS; Rumunu, J; Martin, S; Wamala, JF; Abubakar, A; Sack, DA; et al. (American Society of Tropical Medicine and Hygiene, 2017-12-04)
      Displaced persons living in camps are at an increased risk of diarrheal diseases. Subclinical carriage of pathogens may contribute to the spread of disease, especially for microbes that require a low infectious dose. Multiplex real-time polymerase chain reaction was performed to detect a panel of 20 bacterial, viral, and protozoal targets, and we report a high prevalence of enteropathogen carriage, including Shigella spp. or enteroinvasive Escherichia coli in 14%, among a sample of 88 asymptomatic individuals in an internally displaced persons camp in South Sudan. Further studies are needed to determine the contribution of such carriage to the spread of disease.
    • "Kala-Azar is a Dishonest Disease": Community Perspectives on Access Barriers to Visceral Leishmaniasis (Kala-Azar) Diagnosis and Care in Southern Gadarif, Sudan

      Sunyoto, T; Adam, GK; Atia, AM; Hamid, Y; Babiker, RA; Abdelrahman, N; Vander Kelen, C; Ritmeijer, K; Alcoba, G; den Boer, M; et al. (American Society of Tropical Medicine and Hygiene, 2018-04-13)
      Early diagnosis and treatment is the principal strategy to control visceral leishmaniasis (VL), or kala-azar in East Africa. As VL strikes remote rural, sparsely populated areas, kala-azar care might not be accessed optimally or timely. We conducted a qualitative study to explore access barriers in a longstanding kala-azar endemic area in southern Gadarif, Sudan. Former kala-azar patients or caretakers, community leaders, and health-care providers were purposively sampled and thematic data analysis was used. Our study participants revealed the multitude of difficulties faced when seeking care. The disease is well known in the area, yet misconceptions about causes and transmission persist. The care-seeking itineraries were not always straightforward: "shopping around" for treatments are common, partly linked to difficulties in diagnosing kala-azar. Kala-azar is perceived to be "hiding," requiring multiple tests and other diseases must be treated first. Negative perceptions on quality of care in the public hospitals prevail, with the unavailability of drugs or staff as the main concern. Delay to seek care remains predominantly linked to economic constraint: albeit treatment is for free, patients have to pay out of pocket for everything else, pushing families further into poverty. Despite increased efforts to tackle the disease over the years, access to quality kala-azar care in this rural Sudanese context remains problematic. The barriers explored in this study are a compelling reminder of the need to boost efforts to address these barriers.
    • Malaria PCR Detection in Cambodian Low-Transmission Settings: Dried Blood Spots Versus Venous Blood Samples

      Canier, Lydie; Khim, Nimol; Kim, Saorin; Eam, Rotha; Khean, Chanra; Loch, Kaknika; Ken, Malen; Pannus, Pieter; Bosman, Philippe; Stassijns, Jorgen; et al. (American Society of Tropical Medicine and Hygiene, 2015-01-05)
      In the context of malaria elimination, novel strategies for detecting very low malaria parasite densities in asymptomatic individuals are needed. One of the major limitations of the malaria parasite detection methods is the volume of blood samples being analyzed. The objective of the study was to compare the diagnostic accuracy of a malaria polymerase chain reaction assay, from dried blood spots (DBS, 5 μL) and different volumes of venous blood (50 μL, 200 μL, and 1 mL). The limit of detection of the polymerase chain reaction assay, using calibrated Plasmodium falciparum blood dilutions, showed that venous blood samples (50 μL, 200 μL, 1 mL) combined with Qiagen extraction methods gave a similar threshold of 100 parasites/mL, ∼100-fold lower than 5 μL DBS/Instagene method. On a set of 521 field samples, collected in two different transmission areas in northern Cambodia, no significant difference in the proportion of parasite carriers, regardless of the methods used was found. The 5 μL DBS method missed 27% of the samples detected by the 1 mL venous blood method, but most of the missed parasites carriers were infected by Plasmodium vivax (84%). The remaining missed P. falciparum parasite carriers (N = 3) were only detected in high-transmission areas.
    • Natural history of a visceral leishmaniasis outbreak in highland Ethiopia

      Herrero, M; Orfanos, G; Argaw, D; Mulugeta, A; Aparicio, P; Parreño, F; Bernal, O; Rubens, D; Pedraza, J; Lima, M A; et al. (American Society of Tropical Medicine and Hygiene, 2009-09-01)
      In May 2005, visceral leishmaniasis (VL) was recognized for the first time in Libo Kemken, Ethiopia, a highland region where only few cases had been reported before. We analyzed records of VL patients treated from May 25, 2005 to December 13, 2007 by the only VL treatment center in the area, maintained by Médecins Sans Frontières-Ethiopia, Operational Center Barcelona-Athens. The median age was 18 years; 77.6% were male. The overall case fatality rate was 4%, but adults 45 years or older were five times as likely to die as 5-29 year olds. Other factors associated with increased mortality included HIV infection, edema, severe malnutrition, pneumonia, tuberculosis, and vomiting. The VL epidemic expanded rapidly over a several-year period, culminating in an epidemic peak in the last third of 2005, spread over two districts, and transformed into a sustained endemic situation by 2007.
    • Out of (West) Africa-Who Lost in the End?

      Olliaro, Piero; Lasry, Estrella; Tiffany, Amanda (American Society of Tropical Medicine and Hygiene, 2014-12-15)
      On October 29, 2014, 4 days before the annual meeting of the American Society of Tropical Medicine and Hygiene (ASTMH) to be held in New Orleans, LA, meeting registrants received an e-mail letter from the Louisiana Department of Health and Hospitals stating "we have requested that any individuals that will be traveling to Louisiana following a trip to the West African countries of Guinea, Liberia, and Sierra Leone or have had contact with an Ebola-infected individual remain in a self-quarantine for the 21 days following their relevant travel history…we see no use in you traveling to New Orleans to simply be confined to your room." This communication made it clear that those recently in countries experiencing the 2014 Ebola epidemic would not be able to participate in the meeting. The ASTMH sent their own communication stating that the Society did not agree with the State's policy, but had no choice but to abide. However inconvenient and upsetting this decision might have been, what really matters transcends the mere disturbance of long-planned schedules. More broadly, we lost on five levels.
    • Screening for Glucose-6-Phosphate Dehydrogenase Deficiency Using Three Detection Methods: A Cross-Sectional Survey in Southwestern Uganda

      Roh, ME; Oyet, C; Orikiriza, P; Wade, M; Mwanga-Amumpaire, J; Boum, Y; Kiwanuka, GN; Parikh, S (American Society of Tropical Medicine and Hygiene, 2016-09-26)
      Despite the potential benefit of primaquine in reducing Plasmodium falciparum transmission and radical cure of Plasmodium vivax and Plasmodium ovale infections, concerns over risk of hemolytic toxicity in individuals with glucose-6-phosphate dehydrogenase deficiency (G6PDd) have hampered its deployment. A cross-sectional survey was conducted in 2014 to assess the G6PDd prevalence among 631 children between 6 and 59 months of age in southwestern Uganda, an area where primaquine may be a promising control measure. G6PDd prevalence was determined using three detection methods: a quantitative G6PD enzyme activity assay (Trinity Biotech(®) G-6-PDH kit), a qualitative point-of-care test (CareStart(™) G6PD rapid diagnostic test [RDT]), and molecular detection of the G6PD A- G202A allele. Qualitative tests were compared with the gold standard quantitative assay. G6PDd prevalence was higher by RDT (8.6%) than by quantitative assay (6.8%), using a < 60% activity threshold. The RDT performed optimally at a < 60% threshold and demonstrated high sensitivity (≥ 90%) and negative predictive values (100%) across three activity thresholds (below 60%, 30%, and 40%). G202A allele frequency was 6.4%, 7.9%, and 6.8% among females, males, and overall, respectively. Notably, over half of the G202A homo-/hemizygous children expressed ≥ 60% enzyme activity. Overall, the CareStart(™) G6PD RDT appears to be a viable screening test to accurately identify individuals with enzyme activities below 60%. The low prevalence of G6PDd across all three diagnostic modalities and absence of severe deficiency in our study suggests that there is little barrier to the use of single-dose primaquine in this region.
    • Sociocultural and Structural Factors Contributing to Delays in Treatment for Children with Severe Malaria: A Qualitative Study in Southwestern Uganda

      Sundararajan, Radhika; Mwanga-Amumpaire, Juliet; Adrama, Harriet; Tumuhairwe, Jackline; Mbabazi, Sheilla; Mworozi, Kenneth; Carroll, Ryan; Bangsberg, David; Boum, Yap; Ware, Norma C (American Society of Tropical Medicine and Hygiene, 2015-03-23)
      Malaria is a leading cause of pediatric mortality, and Uganda has the highest incidences in the world. Increased morbidity and mortality are associated with delays to care. This qualitative study sought to characterize barriers to prompt allopathic care for children hospitalized with severe malaria in the endemic region of southwestern Uganda. Minimally structured, qualitative interviews were conducted with guardians of children admitted to a regional hospital with severe malaria. Using an inductive and content analytic approach, transcripts were analyzed to identify and define categories that explain delayed care. These categories represented two broad themes: sociocultural and structural factors. Sociocultural factors were 1) interviewee's distinctions of "traditional" versus "hospital" illnesses, which were mutually exclusive and 2) generational conflict, where deference to one's elders, who recommended traditional medicine, was expected. Structural factors were 1) inadequate distribution of health-care resources, 2) impoverishment limiting escalation of care, and 3) financial impact of illness on household economies. These factors perpetuate a cycle of illness, debt, and poverty consistent with a model of structural violence. Our findings inform a number of potential interventions that could alleviate the burden of this preventable, but often fatal, illness. Such interventions could be beneficial in similarly endemic, low-resource settings.
    • Spatial targeted vector control is able to reduce malaria prevalence in the highlands of Burundi.

      Protopopoff, N; Van Bortel, W; Marcotty, T; Van Herp, M; Maes, P; Baza, D; D'Alessandro, U; Coosemans, M; Department of Parasitology, Institute of Tropical Medicine, Antwerp, Belgium. nprotopopoff@itg.be (American Society of Tropical Medicine and Hygiene, 2008-07)
      In a highland province of Burundi, indoor residual spraying and long-lasting insecticidal net distribution were targeted in the valley, aiming also to protect the population living on the hilltops. The impact on malaria indicators was assessed, and the potential additional effect of nets evaluated. After the intervention--and compared with the control valleys--children 1-9 years old in the treated valleys had lower risks of malaria infection (odds ratio, OR: 0.55), high parasite density (OR: 0.48), and clinical malaria (OR: 0.57). The impact on malaria prevalence was even higher in infants (OR: 0.14). Using nets did not confer an additional protective effect to spraying. Targeted vector control had a major impact on malaria in the high-risk valleys but not in the less-exposed hilltops. Investment in targeted and regular control measures associated with effective case management should be able to control malaria in the highlands.
    • Systematic, Point-of-Care Urine Lipoarabinomannan (Alere TB-LAM) Assay for Diagnosing Tuberculosis in Severely Immunocompromised HIV-Positive Ambulatory Patients

      Huerga, H; Cossa, L; Manhica, I; Bastard, M; Telnov, A; Molfino, L; Sanchez-Padilla, E (American Society of Tropical Medicine and Hygiene, 2020-01-20)
      Point-of-care urine-lipoarabinomannan (LAM) Alere Determine TB-LAM assay has shown utility diagnosing tuberculosis (TB) in HIV-positive, severely immunocompromised, TB-symptomatic patients. We assessed LAM results in severely immunocompromised patients, who had LAM systematically performed at new or follow-up HIV consultations. This was a prospective, observational study on consecutive ambulatory, > 15-year-old HIV-positive patients with CD4 < 100 cells/µL in Mozambique. Clinical assessments and LAM were performed for all and microscopy, Xpert, sputum culture, and chest X-ray for LAM-positive participants. Patients were followed up for 6 months. Of 360 patients, half were ART-naive. Lipoarabinomannan positivity was 11.9% (43/360), higher among symptomatic patients compared with asymptomatic: 18.5% (30/162), and 6.6% (13/198), respectively, P = 0.001. Tuberculosis was bacteriologically confirmed in 6/35 LAM-positive patients (2 of them asymptomatic). Lipoarabinomannan positivity was associated with higher risk of mortality (aOR:4.48, 95% CI: 1.24-16.23, P = 0.022). Systematic urine-LAM allows for rapid TB treatment initiation in severely immunocompromised HIV ambulatory patients and identifies patients at a higher risk of death.
    • Treatment of Kala-azar in Southern Sudan Using a 17-day Regimen of Sodium Stibogluconate Combined with Paromomycin: A Retrospective Comparison with 30-day Sodium Stibogluconate Monotherapy.

      Melaku, Y; Collin, S; Keus, K; Gatluak, F; Ritmeijer, K; Davidson, R N; Médecins sans Frontières-Holland, Amsterdam, The Netherlands. (American Society of Tropical Medicine and Hygiene, 2007-07)
      Médecins sans Frontières-Holland has treated > 67,000 patients with kala-azar (KA) in southern Sudan since 1989. In 2002, we replaced the standard regimen of 30 days of daily sodium stibogluconate (SSG) with a 17-day regimen of daily SSG combined with paromomycin (PM). We analyzed data for 4,263 primary KA patients treated between 2002 and 2005 in southern Sudan to determine the relative efficacy of the combination therapy regimen (PM/SSG). The initial cure rate among patients treated with PM/SSG was 97.0% compared with 92.4% among patients treated with SSG monotherapy. Relative efficacy of PM/SSG compared with SSG increased over the study period: odds of death in the PM/SSG group were 44% lower (odds ratio [OR] = 0.56, 95% confidence interval [CI] = 0.37-0.84) in 2002, 78% lower (OR = 0.22, 95% CI = 0.10-0.50) in 2003, and 86% lower (OR = 0.14, 95% CI = 0.07-0.27) in 2004-2005. In remote field settings, 17 days of SSG combined with PM gives better survival and initial cure rates than 30 days of SSG monotherapy.
    • Viral load for HIV treatment failure management: a report of eight drug-resistant tuberculosis cases co-infected with HIV requiring second-line antiretroviral treatment in Mumbai, India

      Andries, Aristomo; Das, Mrinalini; Isaakidis, Petros; Saranchuk, Peter (American Society of Tropical Medicine and Hygiene, 2013-12)
    • What is a Hotspot Anyway?

      Lessler, J; Azman, A; McKay, H; Moore, S (American Society of Tropical Medicine and Hygiene, 2017-06)
      AbstractThe importance of spatial clusters, or "hotspots," in infectious disease epidemiology has been increasingly recognized, and targeting hotspots is often seen as an important component of disease-control strategies. However, the precise meaning of "hotspot" varies widely in current research and policy documents. Hotspots have been variously described as areas of elevated incidence or prevalence, higher transmission efficiency or risk, or higher probability of disease emergence. This ambiguity has led to confusion and may result in mistaken inferences regarding the best way to target interventions. We surveyed the literature on epidemiologic hotspots, examining the multitude of ways in which the term is used; and highlight the difference in the geographic scale of hotspots and the properties they are supposed to have. In response to the diversity in the term's usage, we advocate the use of more precise terms, such as "burden hotspot," "transmission hotspot," and "emergence hotspot," as well as explicit specification of the spatiotemporal scale of interest. Increased precision in terminology is needed to ensure clear and effective policies for disease control.