Undifferentiated tropical febrile illness in Cordoba, Colombia: Not everything is dengue

Hantavirus and Leptospira are important causes of nonspecific acute febrile syndrome, Meta, Colombia

INTRODUCTION

Acute undifferentiated febrile illnesses are fevers lasting less than fourteen days without an evident focus of infection on the initial physical examination or with inconclusive laboratory tests.

OBJECTIVE

Carry out epidemiological surveillance of the etiology of acute undifferentiated febrile syndrome in the Meta department.

METHODS

A descriptive, prospective cross-sectional study was carried out between February 2021 and June 2023 in a first-level hospital in the department of Meta, Colombia. All enrolled patients underwent routine hematology and blood biochemistry examinations. RT-qPCR was performed for Dengue and serology for laboratory diagnoses using ELISA and MAT for Hantavirus and Leptospirosis, respectively. A descriptive and bivariate analysis was performed using SPSS vr 23.0.

RESULTS

Of the study's total of one hundred patients, 14 % showed antibodies against hantavirus IgG, of which two were seroconverted. In addition, a risk factor OR = 8.3 (CI = 1.8-38.4) for Hantavirus was found in those patients who had contact with farm animals. Regarding leptospirosis, 3 % of the sera agglutinated with titers greater than 1:400, resulting in a primary infection; 11 % of the sera presented agglutination with titers no greater than 1:200 as exposure to leptospirosis. The bivariate analysis showed an OR = 2.4; CI = 0.75-7.4 with water recreational activities in the last 30 days before the onset of symptoms.

CONCLUSIONS

Our study demonstrates the importance of Hantavirus, Dengue, and leptospirosis as a cause of acute undifferentiated febrile illnesses. Coinfections are frequent in one of the tropical areas of Colombia, so it is crucial to establish a more precise diagnosis.

Unexpected arboviruses found in an epidemiological surveillance of acute tropical febrile syndrome in the department of Meta, Eastern Colombia

BACKGROUND

Nonspecific acute tropical febrile illnesses (NEATFI) are common in the Latin American tropics. Dengue, Chikungunya, Zika, Mayaro, and Usutu, among others, can coexist in the American tropics. This study aimed to surveil the arboviruses that cause| acute febrile syndrome in patients in the Meta department, Colombia.

METHODS

Between June 2021 and February 2023, an epidemiological surveillance study was conducted in the Llanos of the Meta department in Eastern Colombia.

RESULTS

One hundred patients in the acute phase with typical prodromal symptoms of NEATFI infection who attended the emergency department of the Villavicencio Departmental Hospital were included. ELISA tests were performed for Dengue, Usutu, Chikungunya, and Mayaro. RT-qPCR was performed to detect the arboviruses Usutu, Dengue, Zika, Mayaro, and Oropouche. The seroprevalence for the Chikungunya, Mayaro, and Usutu viruses was 41 % (28/68), 40 % (27/67), and 62 % (47/75), respectively. Seroconversion for Chikungunya was observed in one patient; two seroconverted to Mayaro and one to Usutu. The NS5 gene fragment of the Usutu virus was detected in nine febrile patients. RT-qPCR of the remaining arboviruses was negative. The clinical symptoms of the nine Usutu-positive patients were very similar to those of Dengue, Chikungunya, Zika, and Mayaro infections.

CONCLUSIONS

The pervasive detection of unexpected viruses such as Usutu and Mayaro demonstrated the importance of searching for other viruses different from Dengue. Because Usutu infection and Mayaro fever have clinical features like Dengue, a new algorithm should be proposed to improve the accuracy of acute tropical fevers.

Molecular Characterization of Leptospira Species among Patients with Acute Undifferentiated Febrile Illness from the Municipality of Villeta, Colombia

Leptospira is a bacterial genus that includes several pathogenic species related to leptospirosis. In Colombia, leptospirosis is a mandatorily reported disease, widely distributed across the country. In the Villeta municipality, leptospirosis has been identified as an important cause of febrile illness; however, to date, no studies have been performed to identify the circulating species. A genus-specific qualitative qPCR was performed on DNA extracted from febrile patients' acute-phase whole-blood samples targeting a fragment of the rrs gene. Positive qPCR samples were further amplified for the adk, icdA, LipL32, LipL41, rrs, and secY genes through conventional PCR for sequencing. All high-quality obtained sequences were further assessed through concatenated phylogenetic analysis. A total of 25% (14/56) of febrile patients' acute blood samples were positive for Leptospira spp. High-quality sequences were obtained for only five genes, and analysis through concatenated phylogeny identified that all sequences clustered within the P1/pathogenic clade; some of them formed a robustly supported clade with Leptospira santarosai, and others were closely related with other Leptospira species but exhibited considerable genetic divergence. We describe the presence of pathogenic Leptospira species among febrile patients from the Villeta municipality and identify L. santarosai and other Leptospira species as causative agents of leptospirosis in the region.

Disease-specific plasma protein profiles in patients with fever after traveling to tropical areas

Fever is common among individuals seeking healthcare after traveling to tropical regions. Despite the association with potentially severe disease, the etiology is often not determined. Plasma protein patterns can be informative to understand the host response to infection and can potentially indicate the pathogen causing the disease. In this study, we measured 49 proteins in the plasma of 124 patients with fever after travel to tropical or subtropical regions. The patients had confirmed diagnoses of either malaria, dengue fever, influenza, bacterial respiratory tract infection, or bacterial gastroenteritis, representing the most common etiologies. We used multivariate and machine learning methods to identify combinations of proteins that contributed to distinguishing infected patients from healthy controls, and each other. Malaria displayed the most unique protein signature, indicating a strong immunoregulatory response with high levels of IL10, sTNFRI and II, and sCD25 but low levels of sCD40L. In contrast, bacterial gastroenteritis had high levels of sCD40L, APRIL, and IFN-γ, while dengue was the only infection with elevated IFN-α2. These results suggest that characterization of the inflammatory profile of individuals with fever can help to identify disease-specific host responses, which in turn can be used to guide future research on diagnostic strategies and therapeutic interventions.

NS1-Specific Antibody Response Facilitates the Identification of Children With Dengue and Zika in Hyperendemic Areas

BACKGROUND

Infections by dengue virus (DENV) and Zika virus (ZIKV) have some similar symptoms and a cross-reactive immune response, although with different risk populations and outcomes. Here, we evaluated the virologic characteristics and the nonstructural protein 1 (NS1)-specific antibody responses to DENV and ZIKV in children suspected of dengue in different epidemiologic moments in Colombia.

METHODS

Viral RNA, circulating NS1 and IgM/IgG specific for DENV and ZIKV were performed by reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) in 301 children suspected of dengue enrolled in a hospital setting during the ZIKV epidemic and a primary healthcare setting during a DENV epidemic. For the detection of DENV and ZIKV-specific IgM, an NS1-based ELISA was validated using characterized pediatric samples. Clinical and laboratory parameters were also evaluated.

RESULTS

DENV RNA or NS1 antigen was detected in the plasma of 62% of children, and in none, the ZIKV RNA was found. NS1-based ELISA for DENV and ZIKV IgM showed a sensitivity/specificity of 90/84% and 73/98%, respectively. Of 114 children without detectable viremia or antigenemia, 30.7%, 17.5%, 22% and 30% were IgM-DENV + , IgM-ZIKV + , IgM-DENV + ZIKV + and IgM-DENV - ZIKV - , respectively. The ZIKV/DENV IgM-NS1 ratio allows the identification of the infecting orthoflavivirus in 88% of the children with IgM-DENV + ZIKV + , confirming a high predominance of DENV infections in the 2 pediatric settings.

CONCLUSION

Overall, 88% of the children with clinical suspicion of dengue had an identifiable orthoflaviviral infection, with 80% caused by DENV, 7% by ZIKV and 0.7% classified as recent infections or coinfection, demonstrating active viral cocirculation in the pediatric population of southern Colombia. The IgM-NS1 detection improved the identification of orthoflaviviral infections in children without viremia or antigenemia, suggesting it is a helpful complementary tool for medical personnel in tropical regions with high viral cocirculation and different clinical scenes.

Acute human leptospirosis in a Caribbean region of Colombia: From classic to emerging risk factors

BACKGROUND

Leptospirosis is a zoonosis of worldwide incidence, with a broad spectrum of health risk factors.

AIM

The objective was to determine risk factors associated with acute human leptospirosis and to explore predictive variables of risk to human leptospirosis.

METHODS

The study was carried out in the Department of Córdoba, in the north of Colombia. We conducted a longitudinal prospective descriptive study with non-probabilistic sampling, which included 339 patients suspected of leptospirosis. Positive cases were confirmed by MAT and PCR. The determination of social and environmental risk factors was done with a survey on epidemiological and environmental variables to establish an association between cases of leptospirosis and risk factors as well as predictive variables.

RESULTS

We found 19.8% (67/339) cases of acute leptospirosis, and the seroprevalence was 27.1% (92/339). The most frequent serogroups were Sejroe, Australis, Pomona, Batavie, Pyrogenes and Grippotyphosa. We identified the following risk factors: age between 10 and 19 years (OR = 2.571; 95% CI); pig ownership (OR = 2.019; 95% CI); bathing or recreational activities in lake/lagoon (OR = 3.85; 95% CI) and in dams (OR = 3.0; 95% CI); floodings 30 days before the onset of symptoms (OR = 2.019; 95% CI), and a mean temperature of 28°C (p 0.044; 95%CI). As significant predictor variables, we identified age (10-19 years), bathing or recreational activities in the lake/lagoon, and flooding 30 days before symptoms were again evidenced. This region presents classic risk factors (pig ownership) and emerging environmental risk factors (recreational practice or bathing in a lake/lagoon and flooding 30 days before the onset of symptoms), and demographic factors such as young age (10-19 years).

CONCLUSIONS

These factors are also predictors of human cases of acute leptospirosis and provide contextual information on environmental and public health that should be considered for epidemiological surveillance in this endemic area.

Fatal acute undifferentiated febrile illness among clinically suspected leptospirosis cases in Colombia, 2016-2019

BACKGROUND

Acute undifferentiated febrile illness is a common challenge for clinicians, especially in tropical and subtropical countries. Incorrect or delayed diagnosis of febrile patients may result in medical complications or preventable deaths. Common causes of acute undifferentiated febrile illness in Colombia include leptospirosis, rickettsioses, dengue fever, malaria, chikungunya, and Zika virus infection. In this study, we described the acute undifferentiated febrile illness in postmortem patients reported as suspected cases of leptospirosis through the national leptospirosis surveillance in Colombia, 2016-2019.

METHODOLOGY/PRINCIPAL FINDINGS

We retrospectively analyze human fresh and formalin-fixed tissue samples from fatal suspected leptospirosis cases reported by the Public Health Laboratories in Colombia. Leptospirosis confirmation was made by immunohistochemistry, real-time polymerase chain reaction (PCR) in the tissue samples. In some cases, the serum sample was used for confirmation by Microagglutination test (MAT). Simultaneously, tissue samples were tested by PCR for the most common viral (dengue, Zika, and chikungunya), bacterial (Brucella spp., and Rickettsia spp.), and parasitic (malaria). Fresh tissue samples from 92 fatal suspected leptospirosis cases were reported to the National Reference Laboratory from 22/32 departments in Colombia. We confirmed leptospirosis in 27% (25/92) of cases. Other pathogens identified by real-time PCR were Brucella spp. (10.9%), Rickettsia spp. (14.1%), and dengue (2.2%). Dengue (6.9%), hepatitis (3.5%), and Yellow Fever cases (2.2%) were detected by the pathology. All patients were negative for chikungunya and Plasmodium spp. Most cases were classified as undifferentiated febrile illnesses (45.7%; 42/92).

CONCLUSIONS/SIGNIFICANCE

This study underscores the importance of early and accurate recognition of leptospirosis to prevent mortalities. Moreover, it draws attention to the existence of other febrile syndromes in Colombia, including rickettsiosis and brucellosis, that currently lack sufficient human surveillance and regular reporting. Expanding laboratory surveillance to include viruses such as Hantavirus, Mayaro virus, Oropouche virus, and West Nile virus is crucial.

Etiologies of Zoonotic Tropical Febrile Illnesses That Are Not Part of the Notifiable Diseases in Colombia

In Colombia, tropical febrile illnesses represent one of the most important causes of clinical attention. Febrile illnesses in the tropics are mainly zoonotic and have a broad etiology. The Colombian surveillance system monitors some notifiable diseases. However, several etiologies are not monitored by this system. In the present review, we describe eleven different etiologies of zoonotic tropical febrile illnesses that are not monitored by the Colombian surveillance system but have scientific, historical, and contemporary data that confirm or suggest their presence in different regions of the country: Anaplasma, Arenavirus, Bartonella, relapsing fever group Borrelia, Coxiella burnetii, Ehrlichia, Hantavirus, Mayaro virus, Orientia, Oropouche virus, and Rickettsia. These could generate a risk for the local population, travelers, and immigrants, due to which they should be included in the mandatory notification system, considering their importance for Colombian public health.

Demographic and clinical risk factors associated with severity of lab-confirmed human leptospirosis in Colombia, 2015-2020

BACKGROUND

Leptospirosis is a common zoonoses and is a major global public health threat. Most cases are mild, typically presenting as a non-specific acute febrile illness. However, leptospirosis can have life-threatening manifestations, including pulmonary hemorrhage syndrome, and acute kidney injury. In Colombia, notification and lab-confirmation of suspected human cases are mandatory. However, little is known about the demographic and clinical factors associated with severe leptospirosis, which could help to reduce clinical complications and mortality. Our aim was to identify risk factors associated with severe leptospirosis, intensive care unit (ICU) admission, and mortality in lab-confirmed cases in Colombia, 2015-2020.

METHODS AND FINDINGS

We analyzed 201 lab-confirmed human leptospirosis cases by microagglutination test. We used a logistic regression to identify the demographic and clinical risk factors associated with severe leptospirosis, admission to ICU, and death. Most leptospirosis confirmed cases occurred in men (85.6%); the mean age was 36.7 years. We classified severe cases (43.3%) by clinical manifestations as renal (29.9%) and liver (27.4%) failure, multiple-organ failure (24.4%), septic shock (24.4%), Weil syndrome (18.4%), pulmonary hemorrhage (18.4%), and meningitis (2.5%), admitted to the ICU (30.3%), and fatal (8.5%). Clinical conditions associated with severe leptospirosis were dyspnea (OR: 5.54; 95% CI: 1.46 to 20.98), tachycardia (OR:9.69; 95% CI: 15.96 to 58.8), and rash (OR: 10.25; 95% CI: 25.01 to 42.08).

CONCLUSIONS

We identified demographic characteristics and clinical symptoms associated with severe leptospirosis in Colombia. We hope these results can support clinicians in providing timely treatment to leptospirosis patients to avoid preventable medical complications or deaths.

Comparison of the Serion IgM ELISA and Microscopic Agglutination Test for diagnosis of Leptospira spp. infections in sera from different geographical origins and estimation of Leptospira seroprevalence in the Wiwa indigenous population from Colombia

Leptospirosis is among the most important zoonotic diseases in (sub-)tropical countries. The research objective was to evaluate the accuracy of the Serion IgM ELISA EST125M against the Microscopic Agglutination Test (MAT = imperfect reference test); to assess its ability to diagnose acute leptospirosis infections and to detect previous exposure to leptospires in an endemic setting. In addition, to estimate the overall Leptospira spp. seroprevalence in the Wiwa indigenous population in North-East Colombia. We analysed serum samples from confirmed leptospirosis patients from the Netherlands (N = 14), blood donor sera from Switzerland (N = 20), and sera from a cross-sectional study in Colombia (N = 321). All leptospirosis ELISA-positive, and a random of negative samples from Colombia were tested by the MAT for confirmation. The ELISA performed with a sensitivity of 100% (95% CI 77% - 100%) and a specificity of 100% (95% CI 83% - 100%) based on MAT confirmed Leptospira spp. positive and negative samples. In the cross-sectional study in Colombia, the ELISA performed with a sensitivity of 100% (95% CI 2–100%) and a specificity of 21% (95% CI 15–28%). Assuming a 5% Leptospira spp. seroprevalence in this population, the positive predictive value was 6% and the negative predictive value 100%. The Leptospira spp. seroprevalence in the Wiwas tested by the ELISA was 39%; however, by MAT only 0.3%. The ELISA is suitable to diagnose leptospirosis in acutely ill patients in Europe several days after onset of disease. For cross-sectional studies it is not recommended due to its low specificity. Despite the evidence of a high leptospirosis prevalence in other study areas and populations in Colombia, the Wiwa do not seem to be highly exposed to Leptospira spp.. Nevertheless, leptospirosis should be considered and tested in patients presenting with febrile illness.

Leptospirosis is among the most important zoonotic diseases in (sub-)tropical countries. The correct diagnosis of leptospirosis is very important to take a medical or public health decision. Therefore, we tested a serological test (ELISA) for its ability to correctly diagnose a negative sample as truly negative and a positive sample as truly positive. We tested the ELISA with European acute leptospirosis confirmed positive and negative samples and compared results with another serological test (microscopic agglutination test), which is the recognized reference test. Further, the ELISA was assessed for its ability to detect previous exposure to leptospires in serum samples from the indigenous Wiwa population from Colombia, where leptospirosis is expected to be endemic.

The ELISA performed very well with sera from patients with acute leptospirosis, however had difficulties to diagnose negative samples as truly negative in the Colombian field samples; hence unexposed persons were falsely diagnosed to be positive. Therefore, we recommend using the ELISA to detect acute leptospirosis several days after onset of illness in a non-endemic environment, but are not convinced of its usefulness to screen a population for previous Leptospira spp. exposure.

Facing the Human and Animal Brucellosis Conundrums: The Forgotten Lessons

Brucellosis is a major zoonotic disease caused by Brucella species. Historically, the disease received over fifty names until it was recognized as a single entity, illustrating its protean manifestations and intricacies, traits that generated conundrums that have remained or re-emerged since they were first described. Here, we examine confusions concerning the clinical picture, serological diagnosis, and incidence of human brucellosis. We also discuss knowledge gaps and prevalent confusions about animal brucellosis, including brucellosis control strategies, the so-called confirmatory tests, and assumptions about the primary-binding assays and DNA detection methods. We describe how doubtfully characterized vaccines have failed to control brucellosis and emphasize how the requisites of controlled safety and protection experiments are generally overlooked. Finally, we briefly discuss the experience demonstrating that S19 remains the best cattle vaccine, while RB51 fails to validate its claimed properties (protection, differentiating infected and vaccinated animals (DIVA), and safety), offering a strong argument against its current widespread use. These conundrums show that knowledge dealing with brucellosis is lost, and previous experience is overlooked or misinterpreted, as illustrated in a significant number of misguided meta-analyses. In a global context of intensifying livestock breeding, such recurrent oversights threaten to increase the impact of brucellosis.

Rickettsial Infections among the Undifferentiated Febrile Patients Attending a Tertiary Care Teaching Hospital of Northern India: A Longitudinal Study

Background

Acute undifferentiated febrile illness (AUFI) is one of the most daunting challenges a physician faces in such settings. Among AUFI, rickettsial infections are most common and related infections (such as anaplasmosis, ehrlichiosis, and Q fever) which are caused by an unusual type of bacteria that can live only inside the cells of another organism. The present study was therefore planned with an objective to estimate the prevalence of rickettsial infection among patients of undifferentiated fever and to determine any association of socio-demographic characteristics with rickettsial disease.

Materials and Methods

Patients presenting with febrile illness and admitted or attending out-patient department of Sher-i-Kashmir Institute of Medical Sciences, Srinagar was approached and recruited in the study. Weil Felix Assay, enzyme-linked immunosorbent assay and indirect immunofluorescence assay were done to detect the anti-rickettsial antibodies. Serological evidence of a fourfold increase in IgG-specific antibody titer reactive with spotted fever group rickettsial antigen by indirect immunofluorescence antibody assays between paired serum specimens was considered a confirmatory diagnosis for the rickettsial disease.

Results

Most of the patients were males 61.6%, and most 46.2% were in the age group of 20 -39 years. Most of the patients, 80.8% belonged to rural areas, and 48% belonged to the upper middle (II) class of the socio-economic class according to modified Kuppuswamy scale. Of the studied participants, a majority, 47.0%, were determined undiagnosed, while 15.4% studied participants were diagnosed to have a rickettsial disease. In patients positive for typhus group, 67.8% were IgM positive, 28.5% were IgG positive, and only 3% were positive for IgM and IgG. In patients positive for Scrub Typhus Group, 32.7% were positive for IgM, and 62.0% were positive for IgG, and only 5.0% were positive for both IgM and IgG. In patients positive for spotted fever group, 36.1% were positive for IgM, and 58.5% were positive for IgG, and only 5.5% were positive for both IgM and IgG. The prevalence of rickettsial disease was found to be 11.3%.

Conclusion

Rickettsial diseases, typhoid and brucellosis, were the most prevalent diseased diagnosed among patients reporting to hospitals with undifferentiated febrile illness. Clinicians must consider rickettsial diseases as one of the differential diagnosis while treating patients with fever.

Prevalence of Malaria and Leptospirosis Co-Infection among Febrile Patients: A Systematic Review and Meta-Analysis

Malaria and leptospirosis are important cosmopolitan infections that have emerged with overlapping geographic distribution, especially in tropical and subtropical regions. Therefore, co-infection with malaria and leptospirosis may occur in overlapping areas. The present study aimed to quantify the prevalence of malaria and leptospirosis co-infection among febrile patients. The association between malaria and leptospirosis infections was also investigated. Relevant studies that had reported malaria and leptospirosis co-infection were identified from PubMed, Scopus, and Web of Science. The risk of bias of the studies was assessed using the Joanna Briggs Institute (JBI) Critical Appraisal Tool. The pooled prevalence of malaria and leptospirosis co-infections among febrile patients and the pooled prevalence of leptospirosis infection among malaria patients were estimated using random effect models. The association between malaria and leptospirosis infection among febrile patients was estimated using random effect models. The outcomes of each study were shown in a forest plot in point estimate and 95% confidence interval (CI). Heterogeneity among the included studies was assessed using Cochran’s Q and quantified using I-squared statistics. For leptospirosis, subgroup analyses of countries, diagnostic tests, and participants’ age groups were performed to specify prevalence in each subgroup. Publication bias was assessed by funnel-plot visualization. Of the 2370 articles identified from the databases, 15 studies met the eligibility criteria and were included for qualitative and quantitative syntheses. Most of the included studies were conducted in India (5/15, 33.3%), Thailand (3/15, 20%), and Cambodia (2/15, 13.3%). Most of the enrolled cases were febrile patients (5838 cases) and malaria-positive patients (421 cases). The meta-analysis showed that the pooled prevalence of malaria and leptospirosis co-infection (86 cases) among febrile patients was 1% (95% CI: 1–2%, I²: 83.3%), while the pooled prevalence of leptospirosis infection (186 cases) among malaria patients was 13% (95% CI: 9–18%, I²: 90.3%). The meta-analysis showed that malaria and leptospirosis co-infections occurred by chance (p: 0.434, OR: 1.4, 95% CI: 0.6–3.28, I²: 85.2%). The prevalence of malaria in leptospirosis co-infection among febrile patients in the included studies was low. Co-infection was likely to occur by chance. However, as clinical symptoms of leptospirosis patients were non-specific and not distinguishable from symptoms of malaria patients, clinicians caring for febrile patients in an area where those two diseases are endemic should maintain a high index of suspicion for both diseases and whether mono-infections or co-infections are likely. Recognition of this co-infection may play an important role in reducing disease severity and treatment duration.

Leptospirosis and rickettsiosis, a diagnostic challenge for febrile syndrome in endemic areas

Se presenta el caso de un hombre de 50 años de edad proveniente de la región de Urabá, Colombia, con una infección mixta por Rickettsia rickettsii y Leptospira interrogans serovar Copenhageni ST78, y pruebas negativas para malaria y dengue.

El paciente presentó un síndrome febril que no mejoró con el tratamiento antibiótico sistémico y, finalmente, falleció en la unidad de cuidados intensivos. El diagnóstico post mortem se hizo mediante tipificación molecular de los dos agentes etiológicos. En la inspección del domicilio del paciente, se encontró un ejemplar de Rattus rattus infectado con L. interrogans del mismo serovar detectado en él. No se encontraron garrapatas en los animales domésticos que habitaban con el paciente.

Se reporta una infección mixta con síntomas clínicos progresivos y fatales en un paciente con antecedentes laborales de riesgo en una zona endémica para enfermedades tropicales, lo que obliga a tener presente la posibilidad de infecciones simultáneas en personas procedentes de áreas endémicas que consulten reiteradamente por síndrome febril sin resolución y tengan riesgo laboral relacionado con actividades agrícolas.

Dengue and hantavirus coinfection with good outcomes: a clinical case from Panama

Dengue and hantavirus are endemic in central Panama. We present a case report of a patient coinfected with dengue and hantavirus who presented overlapping clinical manifestations of both infections. The patient did not require intensive care-as it is commonplace during hantavirus pulmonary syndrome-and he had a good outcome. Patient's care was positively impacted due to correct diagnosis of coinfection. This case highlights that in endemic areas, coinfection with dengue virus and hantavirus should be suspected. To the best of our knowledge, this case is the first documented case of coinfection with dengue virus and hantavirus in Central America.

Effects of Accounting for Interval-Censored Antibody Titer Decay on Seroincidence in a Longitudinal Cohort Study of Leptospirosis

Accurate measurements of seroincidence are critical for infections undercounted by reported cases, such as influenza, arboviral diseases, and leptospirosis. However, conventional methods of interpreting paired serological samples do not account for antibody titer decay, resulting in underestimated seroincidence rates. To improve interpretation of paired sera, we modeled exponential decay of interval-censored microscopic agglutination test titers using a historical data set of leptospirosis cases traced to a point source exposure in Italy in 1984. We then applied that decay rate to a longitudinal cohort study conducted in a high-transmission setting in Salvador, Brazil (2013-2015). We estimated a decay constant of 0.926 (95% confidence interval: 0.918, 0.934) titer dilutions per month. Accounting for decay in the cohort increased the mean infection rate to 1.21 times the conventionally defined rate over 6-month intervals (range, 1.10-1.36) and 1.82 times that rate over 12-month intervals (range, 1.65-2.07). Improved estimates of infection in longitudinal data have broad epidemiologic implications, including comparing studies with different sampling intervals, improving sample size estimation, and determining risk factors for infection and the role of acquired immunity. Our method of estimating and accounting for titer decay is generalizable to other infections defined using interval-censored serological assays.

Two Cases of Natural Infection of Dengue-2 Virus in Bats in the Colombian Caribbean

Dengue, a mosquito-borne zoonotic disease, is the most common vector-borne disease in tropical and subtropical areas. In this study, we aim to demonstrate biological evidence of dengue virus infection in bats. A cross-sectional study was carried out in the departments of Cordoba and Sucre, Colombia. A total of 286 bats were captured following the ethical protocols of animal experimentation. The specimens were identified and euthanized using a pharmacological treatment with atropine, acepromazine and sodium pentobarbital. Duplicate samples of brain, heart, lung, spleen, liver, and kidney were collected with one set stored in Trizol and the other stored in 10% buffered formalin for histopathological and immunohistochemical analysis using polyclonal antibodies. Brain samples from lactating mice with an intracranial inoculation of DENV-2 were used as a positive control. As a negative control, lactating mouse brains without inoculation and bats brains negative for RT-PCR were included. Tissue sections from each specimen of bat without conjugate were used as staining control. In a specimen of Carollia perspicillata captured in Ayapel (Cordoba) and Phylostomus discolor captured in San Carlos (Cordoba), dengue virus was detected, and sequences were matched to DENV serotype 2. In bats RT-PCR positive for dengue, lesions compatible with viral infections, and the presence of antigens in tissues were observed. Molecular findings, pathological lesions, and detection of antigens in tissues could demonstrate viral DENV-2 replication and may correspond to natural infection in bats. Additional studies are needed to elucidate the exact role of these species in dengue epidemics.

Co-circulation and misdiagnosis led to underestimation of the 2015-2017 Zika epidemic in the Americas

During the 2015-2017 Zika epidemic, dengue and chikungunya-two other viral diseases with the same vector as Zika-were also in circulation. Clinical presentation of these diseases can vary from person to person in terms of symptoms and severity, making it difficult to differentially diagnose them. Under these circumstances, it is possible that numerous cases of Zika could have been misdiagnosed as dengue or chikungunya, or vice versa. Given the importance of surveillance data for informing epidemiological analyses, our aim was to quantify the potential extent of misdiagnosis during this epidemic. Using basic principles of probability and empirical estimates of diagnostic sensitivity and specificity, we generated revised estimates of reported cases of Zika that accounted for the accuracy of diagnoses made on the basis of clinical presentation with or without laboratory confirmation. Applying this method to weekly reported case data from 43 countries throughout Latin America and the Caribbean, we estimated that 944,700 (95% CrI: 884,900-996,400) Zika cases occurred when assuming all confirmed cases were diagnosed using molecular methods versus 608,400 (95% CrI: 442,000-821,800) Zika cases that occurred when assuming all confirmed cases were diagnosed using serological methods. Our results imply that misdiagnosis was more common in countries with proportionally higher reported cases of dengue and chikungunya, such as Brazil. Given that Zika, dengue, and chikungunya appear likely to co-circulate in the Americas and elsewhere for years to come, our methodology has the potential to enhance the interpretation of passive surveillance data for these diseases going forward. Likewise, our methodology could also be used to help resolve transmission dynamics of other co-circulating diseases with similarities in symptomatology and potential for misdiagnosis.

Viral etiology and seasonal trends of pediatric acute febrile illness in southern Puerto Rico; a seven-year review

BACKGROUND

Acute febrile illness (AFI) is an important cause for seeking health care among children. Knowledge of the most common etiologic agents of AFI and its seasonality is limited in most tropical regions.

METHODOLOGY/PRINCIPAL FINDINGS

To describe the viral etiology of AFI in pediatric patients (≤18 years) recruited through a sentinel enhanced dengue surveillance system (SEDSS) in Southern Puerto Rico, we analyzed data for patients enrolled from 2012 to May 2018. To identify seasonal patterns, we applied time-series analyses to monthly arboviral and respiratory infection case data. We calculated coherence and phase differences for paired time-series to quantify the association between each time series. A viral pathogen was found in 47% of the 14,738 patients. Influenza A virus was the most common pathogen detected (26%). The incidence of Zika and dengue virus etiologies increased with age. Arboviral infections peaked between June and September throughout the times-series. Respiratory infections have seasonal peaks occurring in the fall and winter months of each year, though patterns vary by individual respiratory pathogen.

CONCLUSIONS/SIGNIFICANCE

Distinct seasonal patterns and differences in relative frequency by age groups seen in this study can guide clinical and laboratory assessment in pediatric patients with AFI in Puerto Rico.

Systematic analysis of disease-specific immunological signatures in patients with febrile illness from Saudi Arabia

Objectives

Little is known about the prevalence of febrile illness in the Arabian region as clinical, laboratory and immunological profiling remains largely uncharacterised.

Methods

A total of 2018 febrile patients from Jazan, Saudi Arabia, were recruited between 2014 and 2017. Patients were screened for dengue and chikungunya virus, Plasmodium, Brucella, Neisseria meningitidis, group A streptococcus and Leptospira. Clinical history and biochemical parameters from blood tests were collected. Patient sera of selected disease-confirmed infections were quantified for immune mediators by multiplex microbead-based immunoassays.

Results

Approximately 20% of febrile patients were tested positive for one of the pathogens, and they presented overlapping clinical and laboratory parameters. Nonetheless, eight disease-specific immune mediators were identified as potential biomarkers for dengue (MIP-1α, MCP-1), malaria (TNF-α), streptococcal and meningococcal (eotaxin, GRO-α, RANTES, SDF-1α and PIGF-1) infections, with high specificity and sensitivity profiles. Notably, based on the conditional inference model, six of these mediators (MIP-1α, TNF-α, GRO-α, RANTES, SDF-1α and PIGF-1) were revealed to be 68.4% accurate in diagnosing different febrile infections, including those of unknown diseases.

Conclusions

This study is the first extensive characterisation of the clinical analysis and immune biomarkers of several clinically important febrile infections in Saudi Arabia. Importantly, an immune signature with robust accuracy, specificity and sensitivity in differentiating several febrile infections was identified, providing useful insights into patient disease management in the Arabian Peninsula.

DENV and ZIKV detection in patients with acute febrile syndrome in Córdoba, Colombia

OBJECTIVE

To determine simultaneous circulation of DENV serotypes and ZIKV in Córdoba, Colombia, during 2015 and 2016.

MATERIAL AND METHODS

A total of 294 samples from patients with clinical diagnosis of febrile syndrome compatible with dengue were collected between June 2015 and December 2016. All samples were tested for DENV and ZIKV by RT-PCR using C6/36 cells culture supernatant.

RESULTS

Thirty-three percent of the samples were positive (97/294); from these, 61.8% were positive for DENV and 31% were positive for Zika. The predominant serotype was DENV-2 (70.1%), followed by DENV-3 (8.9%), DENV-4 (6%), and DENV-1 (3%). DENV/ZIKV coinfection was identified in 7.2% of the cases associated with DENV-1 and DENV-3 serotypes. The confirmed cases of dengue, Zika, and DENV/ZIKV coinfections were clinically mild and self-limited.

CONCLUSIONS

We reported the co-circulation of all four DENV serotypes, with a higher frequency of DENV-2, and ZIKV introduction in Córdoba department-Colombia in August 2015. This scenario favored the appearance of DENV/ZIKV coinfections.

Acceptability and usability of a mobile application for management and surveillance of vector-borne diseases in Colombia: An implementation study

BACKGROUND

Vector-borne diseases are a public health problem in Colombia, where dengue virus infection is hyperendemic. The introduction of other arboviruses, such as chikungunya and Zika in the last three years, has aggravated the situation. Mobile health (mHealth) offers new strategies for strengthening health care and surveillance systems promoting the collection, delivery, and access of health information to professionals, researchers, and patients. Assessing mobile application performance has been a challenge in low- and middle-income countries due to the difficulty of implementing these technologies in different clinical settings. In this study, we evaluate the usability and acceptability of a mobile application, FeverDX, as a support tool in the management of patients with febrile syndrome and suspected arboviruses infection by general practitioners from Colombia.

METHODS

A pilot implementation study was conducted to evaluate the usability and acceptability of FeverDX using the modified version of the Mobile Application Rating Scale (uMARS). The evaluation form included 25 questions regarding quantity and quality of information, engagement, functionality, aesthetics, impact, and acceptability by healthcare workers. Each item uses a 5-point scale (1-Inadequate, 2-Poor, 3-Acceptable, 4-Good, 5-Excellent). A global score was obtained for the evaluation form test by determining the median scores of each subsection. A descriptive statistical analysis of the data obtained was performed.

RESULTS

Between December 2016 and January 2017, a total of 20 general practitioners from the Emergency room and hospitalization areas evaluated FeverDX. Less than half (9/20) of the evaluators had a comprehensive knowledge of the Colombian Ministry of Health's guidelines for the diagnosis and management of arboviruses, and evaluators partially (4/9) or completely (5/9) agreed that the content of the application follows the management guidelines. On uMARS scale, FeverDX excelled regarding impact (median 5; IQR = 5-5), functionality (median 5; IQR = 4.8-5), and information and scientific basis (median 4; IQR = 4-4). FeverDX scored well regarding user feedback (median 4; IQR = 4-4.5), design and aesthetics (median 4; IQR = 4-4.3), and subjective assessment of quality (median 4.5; IQR = 4.3-4.8).

CONCLUSIONS

FeverDX, a mobile application, is a novel mHealth strategy to strengthen care processes and facilitate the detection and reporting of notifiable surveillance diseases. It could improve adherence to clinical practice guidelines for the management and prevention of prevalent diseases as arboviruses in healthcare settings. Although this pilot study used a small sample size, FeverDx performed adequately in a simulated emergency consultation. Further implementation studies are needed to increase the reliability of mHealth technologies in different scenarios.

Assessment of Hematological Parameters in Malaria, among Adult Patients Attending the Bamenda Regional Hospital

Malaria, which is responsible for a substantial amount of deaths in endemic countries, has been shown to have both direct and indirect effects on the hematological parameters. Notwithstanding, some hematological parameters among populations living in malaria endemic regions have not been described consistently, as a standard for measuring malaria burden. Based on the above fact, this study was designed to assess some hematological changes and their diagnostic values in malaria infected patients. A total of 160 malaria positive adult patients, together with 81 healthy control adults were recruited for the study. For the malaria positive group, the female to male ratio was 1.38 : 1. Specifically, 74.38%, 10.00%, and 15.62% of those in the malaria positive group had mild, moderate, and severe parasitaemia, respectively. Leukemia, anemia, and thrombocytopenia were found to be significantly associated with malaria and were all estimated to be specific for the diagnosis of malaria. Anemia was, however, estimated to be both sensitive and specific for malaria diagnosis. Therefore, anemia offers the most diagnostic value in the malaria infected patients of this study.

Evaluation of serological test of Zika in an endemic area of flavivirus in the Colombian Caribbean

Abstract

The Zika virus (ZIKV) is an emerging flavivirus transmitted primarily through arthropods, endemic in Africa, Asia, and the Americas, and is considered a global threat by the World Health Organization.

Objective

To evaluate a commercial Zika virus test (IgG/IgM catalog number B815C, Biocan, Canada.

Methods

We evaluated 30 sera of patients diagnosed with Dengue, Leptospira, Malaria, Hantavirus, and Chikungunya. To establish the sensitivity of the test, two groups of sera were analyzed, the first one was patients with Zika RT-qPCR positive, and the second were patients RT-qPCR negative but with clinical suspicion of Zika.

Results

The specificity was of 23.3% (7/30), the sensitivity in acute patients with positive RT-qPCR was of 63.6%, the patients with clinical suspicion of Zika the sensitivity (IgM) was of 80% (n = 8/10). Overall sensitivity (IgM) of both groups was of 71.4% (15/21).

Conclusions

The test showed a low specificity to be used as a serological test in an endemic area of flavivirus infection.

Occupational history of exposure to zoonotic agents in people dedicated to livestock in San Pedro de los Milagros, Antioquia, Colombia

Introduction: According to the World Health Organization, livestock farming is one of the anthropic activities in which workers are exposed to various zoonotic agents.Objectives: To establish the frequency of seropositivity (IgG antibodies) against some zoonotic agents in people with occupational exposure to livestock in San Pedro de los Milagros (Antioquia), and to analyze associated factors.Materials and methods: Descriptive study carried out on a population of 328 cattle farmers. Demographic data were collected and the seropositivity frequency of IgG antibodies to Babesia bovis, Babesia bigemina, Anaplasma phagocytophilum, Ehrlichia chaffensis, Borrelia burgdorferi, Coxiella burnetii, Francisella tularensis, Brucella abortus, Brucella suis, Leptospira interrogans, and Toxoplasma gondii was determined. Overall and specific prevalence, prevalence ratios and binary logistic regressions were estimated.Results: The highest seropositivity frequencies were 47.6% for T. gondii, 33.5% for B. burgdorferi and 13% for E. chaffensis. The prevalence of T. gondii and B. burgdorferi had statistical association with sex [RP:1.3 (CI:1.0-1.8) and 2.0 (CI:1.1-3.9) respectively], and age group [(RP:1.5 (CI:1.2-1,9) and 2.5 (CI:1.4-6.4) respectively]. In workers with more than 10 years of related work experience, statistical association was 50% [RP:1.5 (CI:1.2-1.9) and 2.5 (CI:1.6-2.3), respectively]. There were no seropositive results for B. abortus, B. suis, B. bovis and B. bigemina.Conclusions: Exposure to some zoonotic agents was evidenced. This is determinant for the knowledge of tropical zoonotic diseases transmitted by vectors in livestock production systems.

Brucellosis in Colombia: Current Status and Challenges in the Control of an Endemic Disease

Brucellosis is a zoonosis of nearly worldwide distribution. The disease is considered to be endemic in most of the developing countries with a substantial impact on both human and animal health as well as on the economy. The aim of this scoping review is to provide an overview of the brucellosis status in Colombia and the factors associated with its persistence, to highlight the strengths and gaps of the adopted countermeasures and to supply evidence to policy-makers on the best approaches to mitigate the disease burden. Due to the presence of brucellosis in several susceptible production livestock systems scattered throughout the country, a plan for its control, prevention and eradication was established almost 20 years ago. However, despite extensive efforts, brucellosis prevalence has fluctuated over the years without any trend of decreasing. The restricted budget allocated for brucellosis control is a limiting factor for the success of the program. For instance, the absence of indemnities for farmers results in infected animals remaining on farms which potentially increases the risk of disease spread. Likewise, disease surveillance is restricted to Brucella abortus and excludes other Brucella species of importance, such as B. melitensis and B. suis. The countermeasures are mostly focused on cattle and only a few actions are in place for the management of brucellosis in other livestock species. In humans, cases of brucellosis are annually diagnosed, although the disease remains highly underreported. High impact educational and training programs are required to address the disease in a comprehensive manner, including vulnerable groups, such as traditional smallholders and low-productivity regions, as well as other stakeholders, such as healthcare and veterinary authorities. Important financial investments based on sustained cooperation between governmental institutions, industry, and farmers are important for developing affordable and effective strategies to control the disease.

Pathogenic Leptospira in Commensal Small Mammals from the Extensively Urbanized Coastal Benin

Leptospirosis is caused by spirochete bacteria of the genus Leptospira that affect one million and kill 60,000 persons annually in the world, who get infected through environmental mammal-excreted (notably rodent) pathogens. Using qPCR and DNA sequencing approaches, we here examine Leptospira occurrence and diversity in 971 commensal small mammals in urban and peri-urban habitats from south Benin, where socio-environmental conditions are favorable for human contamination. Prevalence reached 12.9% on average, but showed very important variations in both space and time, thus pointing toward a role of local processes in the maintenance and circulation of rodent-borne leptospires in the area. Prevalence peaks may occur during or one month after moderate (100–200 mm) monthly rainfall, suggesting that rodent-borne leptospires may be more prevalent when standing waters are present, but not at their highest levels (i.e., floods). However, this pattern will have to be confirmed through proper diachronic analysis. Finally, an incomplete but significant host-specificity was observed, with L. kirschneri retrieved only in African shrews, and the invasive Rattus norvegicus and the native Mastomys natalensis preferentially infected by L. interrogans and L. borgpeterseni, respectively. Our study highlights the urgent need for investigations on human leptospirosis in the extensively urbanized Abidjan–Lagos corridor.

Dengue Virus in Bats from Córdoba and Sucre, Colombia

Natural infection of dengue virus (DENV) in bats is an unexplored field in Colombia. To detect the presence of DENV in bats, a descriptive prospective study using a nonprobabilistic sampling was carried out; 286 bats in 12 sites were caught. Sample tissues of different animals were obtained; the RNA was obtained from tissues and a nested-RT-PCR was carried out and detected amplicons of 143 fragment of the NS5 gene were sequenced by the Sanger method. In nonhematophagous bats Carollia perspicillata and Phyllostomus discolor captured in Ayapel and San Carlos (Córdoba), respectively, an amplicon corresponding to NS5 was detected. The amplicons showed a high similarity with serotype-2 dengue virus (DENV-2). This is the first evidence of the DENV-2 genome in bats in from the Colombian Caribbean.

First report of Culex flavivirus infection from Culex coronator (Diptera: Culicidae), Colombia

BACKGROUND

Flaviviruses are important pathogens for humans and animals (Dengue viruses, Yellow fever virus, Zika virus and West Nile virus). Culex flavivirus (CxFV) is an insect-specific virus of the genus Flavivirus, detected in a wide variety of mosquito species.

OBJECTIVE

To detect Flavivirus in mosquitoes of a tropical region of the Colombian Caribbean.

METHODS

In 2014, an entomological surveillance of arboviruses was conducted in the department of Cordoba area of the Caribbean, Colombia. A total of 8270 mosquitoes were captured as follow: Mansonia (n = 3271/39.5%), Culex (n = 2668/32.26%), Anopheles (n = 840/10.15%), Aedeomyia (n = 411/4.9%), Psorophora (n = 397/4.8%), Coquilletidia (n = 369/4.46%), Uranotaenia (n = 261/3.15%) and Aedes (n = 53/0.6%). All mosquito species were collected in dry tropical forest of the Caribbean area. Universal primers for NS5 gene (958 pb), RT-PCR for flavivirus and sequencing were used for molecular identification of viruses detected.

RESULTS

Two pools belonging to Culex coronator were positive for flavivirus RNA sequence by RT-PCR. The sequences of the PCR amplicons, matched that of the Culex flaviviruses, CxFv COL PM_149 (GenBank: KR014201) and CxFv COL PM_212 (GenBank: KT307717). Phylogenetic analysis of the NS5 protein sequences of the Culex flaviviruses sequences with those of reference sequences available in GenBank indicated viruses of Genotype II, closely related to the Brazilian strain, BR_SJRP_01_ (GenBank: KT726939), from Culex sp. The alignment of Culex flavivirus sequences CxFv COL_ PM 212 and CxFv COL_ PM 149 with sequences of strains detected in different geographical regions grouped the strains in a Latin American clade reported in Brazil, Argentina and Mexico.

CONCLUSIONS

The present work illustrated that CxFV was circulating among vectors of human pathogenic arboviruses in Colombia, but the impact of CxFV on other flaviviruses which are endemic in the study area still remains to be explored.

Neighborhood Violence Impacts Disease Control and Surveillance: Case Study of Cali, Colombia from 2014 to 2016

Arboviruses are responsible for a large burden of disease globally and are thus subject to intense epidemiological scrutiny. However, a variable notably absent from most epidemiological analyses has been the impact of violence on arboviral transmission and surveillance. Violence impedes surveillance and delivery of health and preventative services and affects an individual’s health-related behaviors when survival takes priority. Moreover, low and middle-income countries bear a disproportionately high burden of violence and related health outcomes, including vector borne diseases. To better understand the epidemiology of arboviral outbreaks in Cali, Colombia, we georeferenced chikungunya (CHIKV), dengue (DENV), and Zika (ZIKV) viral cases from The National System of Surveillance in Public Health between October 2014 and April 2016. We extracted homicide data from the municipal monthly reports and kernel density of homicide distribution from IdeasPaz. Crucially, an overall higher risk of homicide is associated with increased risk of reported DENV, lower rates of acute testing, and higher rates of lab versus clinical discordance. In the context of high violence as a potential barrier to access to preventive health services, a community approach to improve health and peace should be considered.

Epidemiological trends and molecular dynamics of dengue, chikungunya virus infection, coinfection, and other undifferentiated fever during 2015-2016 in Odisha, India

Chikungunya virus (CHIKV) infection is spatiotemporally related to dengue virus (DENV) infection and mostly undiagnosed due to similar primary symptoms. In 2013, a high rate (36%) of coinfection of DENV and CHIKV was reported in Odisha. Hence, the hospital-based study was continued to synthesis current epidemiological understanding of their single distribution or coinfection. Suspected DENV patients serum samples were tested for DENV and CHIKV by serology and reverse-transcription polymerase chain reaction. The positive samples were used for analysis of mutation, selection pressure, and phylogenetic relationship. Clinical information was also analyzed. Among 648 (2015 and 2016) suspected DENV patients, 141 (21.7%) were positive for DENV (serotypes 1-3), 22 (3.4%) were positive for CHIKV (ECSA) and 4 (2.8%) were coinfected with both. Sequence analysis showed four consistent mutations (M104V, V112A, K166N, and F169L) in CprM gene of DENV 2 and two consistent mutations (M269V, D284E) in E1 gene of CHIKV. Interestingly, the CHIKV- E1 A226V mutation was absent in the studied population. It was also noticed that the peak incidence of both the infections occurs in August-September in 2015-16. Moreover, Plasmodium species, Salmonella typhi, and Rickettsial typhi infections were also observed in DENV patients. Different etiology was also detected in other undifferentiated fever patients as mixed infections (malaria, S. typhi, and R. typhi ). Hence, this investigation shows the significant reduction of DENV-CHIKV coinfection as compared with previous report, the burden of arboviruses and acute undifferentiated fever in Odisha in 2015-2016, highlighting the importance of epidemiological picture of febrile patients for appropriate patient management.

Clinical and Epidemiological Status of Leptospirosis in a Tropical Caribbean Area of Colombia

Objective

To describe and analyze the clinical and epidemiological status in 28 confirmed cases of human leptospirosis at the main public hospital of Cordoba.

Methods

Between 2012 and 2013, we conducted an active surveillance at the main hospital of Cordoba to establish the etiologic diagnosis of the undifferentiated tropical febrile illness (UTFI) cases. UTFI is defined as a fever without an infection focus in the initial physical examination or in basic laboratory tests. Patients in acute phase were accompanied by prodromal symptoms, including myalgia, arthralgia, headache, asthenia, chills, icterus, dyspnea, abdominal pain, rash, and nausea. Samples were collected on admission and at discharge. Clinical and epidemiological data were collected for each patient. Microscopic agglutination test (MAT) was performed.

Results

The 28 leptospirosis cases presented the following gender distribution: male (n=24) and female (n=4). The duration of hospitalization was 10.39 days. The main symptoms and clinical manifestations were fever, headache and nausea, vomiting, and abdominal pain, all of which occurred in up to 60% of patients. Of the 28 cases studied, 4 were fatal. The most frequent infecting serogroups were Ballum and Canicola.

Conclusion

Leptospirosis is a common cause of undifferentiated tropical febrile illness in Colombia; it is important to establish ongoing and accurate surveillance for acute febrile illness to facilitate the detection of cases of leptospirosis.

Epidemiology of acute febrile illness in Latin America

Background

The causes of acute febrile illness (AFI) in Latin America are diverse and their complexity increases as the proportion of fever due to malaria decreases, as malaria control measures and new pathogens emerge in the region. In this context, it is important to shed light on the gaps in the epidemiological characteristics and the geographic range for many AFI aetiologies.

Objectives

To review studies on community-acquired fever aetiology other than malaria in Latin America, and to highlight knowledge gaps and challenges needing further investigation.

Sources

PubMed from 2012 to April 2018.

Content

We found 17 eligible studies describing 13 539 patients. The median number of pathogens tested per individual was 3.5 (range 2–17). A causative pathogen could be determined for 6661 (49.2%) individuals. The most frequently reported pathogen during the study periods was dengue virus (DENV) (14 studies), followed by chikungunya virus (nine studies) and Zika virus (seven studies). Among the studies reporting concurrent infections, 296 individuals (2.2%) were found to have co-infections. In-hospital mortality was reported in eight (47%) studies, ranging between 0% and 18%.

Implications

DENV fever is the febrile illness most frequently reported, reflecting its importance, while chikungunya and zika viruses present increasing trends since their emergence in the region. Studies with systematic and harmonized approaches for detection of multiple pathogens are needed and would probably reveal a higher burden of neglected pathogens such as Rickettsia spp. and arenaviruses. The lack of point-of-care tests and harmonized approach limits the care provided by health professionals and the efficacy of surveillance for AFI in the region.

Epidemiologic profile and clinical course of four confirmed rickettsiosis cases in Southern Mexico during 2016

Domestic animals can carry ticks or fleas, which constitute common vectors of rickettsial infections. The contact with them should be considered as suggestive of rickettsial infections in symptomatic patients. Misdiagnosis might occur in regions where other vector-borne diseases are endemic. Anamnesis is essential for an accurate clinical diagnosis.

Zika virus disease, microcephaly and Guillain-Barré syndrome in Colombia: epidemiological situation during 21 months of the Zika virus outbreak, 2015-2017

Background

The Zika virus disease (ZVD) has had a huge impact on public health in Colombia for the numbers of people affected and the presentation of Guillain-Barre syndrome (GBS) and microcephaly cases associated to ZVD.

Methods

A retrospective descriptive study was carried out, we analyze the epidemiological situation of ZVD and its association with microcephaly and GBS during a 21-month period, from October 2015 to June 2017. The variables studied were: (i) ZVD cases, (ii) ZVD cases in pregnant women, (iii) laboratory-confirmed ZVD in pregnant women, (iv) ZVD cases associated with microcephaly, (v) laboratory-confirmed ZVD associated with microcephaly, and (vi) ZVD associated to GBS cases. Average number of cases, attack rates (AR) and proportions were also calculated. The studied variables were plotted by epidemiological weeks and months. The distribution of ZVD cases in Colombia was mapped across the time using Kernel density estimator and QGIS software; we adopted Kernel Ridge Regression (KRR) and the Gaussian Kernel to estimate the number of Guillain Barre cases given the number of ZVD cases.

Results

One hundred eight thousand eighty-seven ZVD cases had been reported in Colombia, including 19,963 (18.5%) in pregnant women, 710 (0.66%) associated with microcephaly (AR, 4.87 cases per 10,000 live births) and 453 (0.42%) ZVD associated to GBS cases (AR, 41.9 GBS cases per 10,000 ZVD cases). It appears the cases of GBS increased in parallel with the cases of ZVD, cases of microcephaly appeared 5 months after recognition of the outbreak. The kernel density map shows that throughout the study period, the states most affected by the Zika outbreak in Colombia were mainly San Andrés and Providencia islands, Casanare, Norte de Santander, Arauca and Huila. The KRR shows that there is no proportional relationship between the number of GBS and ZVD cases. During the cross validation, the RMSE achieved for the second order polynomial kernel, the linear kernel, the sigmoid kernel, and the Gaussian kernel are 9.15, 9.2, 10.7, and 7.2 respectively.

Conclusions

This study updates the epidemiological analysis of the ZVD situation in Colombia describes the geographical distribution of ZVD and shows the functional relationship between ZVD cases and GBS.