Incidence Of Yellow Fever Research Articles

Yellow fever virus disease: a systematic review of reemergence, incidence and mortality in Isiolo county, Kenya

Yellow fever is an endemic arboviral disease caused by yellow fever virus (YFV), with high fatality. WHO (Eliminate Yellow Fever Epidemics) is a plan to control YFV, with strategies to be carried out from 2017 to 2026. YFV outbreaks occurred in nine African countries in 2021. The burden was estimated in 2013 to be between 84,000 and 170,000 severe cases and 29,000 to 60,000 deaths. Most of the world’s cases were reported in West and East Africa. Understanding the occurrence of yellow fever epidemics is critical for targeted interventions and control efforts to reduce the burden of disease. A systematic review study design was used to review existing literature and data on the yellow fever incidence and mortality rates in the region. Predictors of occurrence of yellow fever outbreaks were identified to include; local mosquito populations and specific yellow fever virus strain, eco climatic conditions, sociopolitical and demographic factors including population size, density, mobility, and vaccine coverage. Kenya declared an outbreak of yellow fever in Isiolo County after the death of three people. About 20 cases were reported in Isiolo in February. Counties bordering Isiolo were placed in the high-risk bracket. A national incident management structure to manage the outbreak was established. The team visited the epicenter of the outbreak in Merti and Garbatulla. Active case search and surveillance was done. It was noted that there was delay in case investigation. This was attributed to low index of suspicion among clinicians. It was concluded that there could be a possibility of both malaria and yellow fever outbreak in the county. The county health team was advised to heighten continued active case search and surveillance, case management and improve on risk communication to the community.

The incidence and mortality of yellow fever in Africa: a systematic review and meta-analysis

BackgroundUnderstanding the occurrence of yellow fever epidemics is critical for targeted interventions and control efforts to reduce the burden of disease. We assessed data on the yellow fever incidence and mortality rates in Africa.MethodsWe searched the Cochrane Library, SCOPUS, MEDLINE, CINAHL, PubMed, Embase, Africa-wide and Web of science databases from 1 January 1975 to 30th October 2020. Two authors extracted data from included studies independently and conducted a meta-analysis.ResultsOf 840 studies identified, 12 studies were deemed eligible for inclusion. The incidence of yellow fever per 100,000 population ranged from < 1 case in Nigeria, < 3 cases in Uganda, 13 cases in Democratic Republic of the Congo, 27 cases in Kenya, 40 cases in Ethiopia, 46 cases in Gambia, 1267 cases in Senegal, and 10,350 cases in Ghana. Case fatality rate associated with yellow fever outbreaks ranged from 10% in Ghana to 86% in Nigeria. The mortality rate ranged from 0.1/100,000 in Nigeria to 2200/100,000 in Ghana.ConclusionThe yellow fever incidence rate is quite constant; in contrast, the fatality rates vary widely across African countries over the study period. Standardized demographic health surveys and surveillance as well as accurate diagnostic measures are essential for early recognition, treatment and control.

Ocorrência de febre amarela no Brasil: uma revisão integrativa da literatura (2014-2018)

Objetivo: Descrever através de uma revisão integrativa de literatura os aspectos da ocorrência da febre amarela no Brasil de 2014 a 2018. Métodos: Realizou-se um levantamento de artigos no período de 2014 a 2018, obtidos na EBSCO contendo as bases de dados: MEDLINE, Academic Search Elite, Dentistry &amp; Oral Sciences Source, Engineering Source, e demais bases como; National Library of Medicine National Health dos EUA (PubMed - NCBI), Biblioteca Virtual da Saúde (BVS), PlosOne, Scientific Eletronic Library Online (SCIELO), no mês de setembro de 2018, utilizando os descritores: Febre Amarela, prevenção, controle, epidemiologia, vacina e Brasil. Resultados: A amostra final foi composta por (12) artigos, (2) falavam sobre controle da febre amarela, (4) sobre aspectos epidemiológicos e (6) sobre imunização. Evidencia-se a relação entre incidência da febre amarela com fatores climáticos, diversidade de hospedeiros primatas não humanos e baixa cobertura vacinal. Conclusão: A cobertura vacinal deficiente em áreas de risco e a falhas nas informações e na descrição dos surtos pelos boletins epidemiológicos favorece o aumento da ocorrência desta doença no período analisado.

Emerging and Reemerging Aedes-Transmitted Arbovirus Infections in the Region of the Americas: Implications for Health Policy.

The increasing geographical spread and disease incidence of arboviral infections are among the greatest public health concerns in the Americas. The region has observed an increasing trend in dengue incidence in the last decades, evolving from low to hyperendemicity. Yellow fever incidence has also intensified in this period, expanding from sylvatic-restricted activity to urban outbreaks. Chikungunya started spreading pandemically in 2005 at an unprecedented pace, reaching the Americas in 2013. The following year, Zika also emerged in the region with an explosive outbreak, carrying devastating congenital abnormalities and neurologic disorders and becoming one of the greatest global health crises in years. The inadequate arbovirus surveillance in the region and the lack of serologic tests to differentiate among viruses poses substantial challenges. The evidence for vector control interventions remains weak. Clinical management remains the mainstay of arboviral disease control. Currently, only yellow fever and dengue vaccines are licensed in the Americas, with several candidate vaccines in clinical trials. The Global Arbovirus Group of Experts provides in this article an overview of progress, challenges, and recommendations on arboviral prevention and control for countries of the Americas.

Cardiac Involvement by Yellow Fever(from the PROVAR+ Study)

Incidence of Yellow Fever (YF) has increased in Brazil, and cardiac findings such as bradyarrhythmias and conduction abnormalities have been described. We aimed to perform a comprehensive cardiac evaluation of patients with YF, and to assess the association between cardiac involvement and disease severity. Patients hospitalized with YF from February to March 2018 underwent clinical and laboratory evaluation, focused bedside echocardiography (GE Vivid IQ), electrocardiogram and, in case of alterations, 24-hours Holter. Patients were divided into 2 groups according to YF severity. Five patients underwent magnetic resonance imaging and 3 had necropsy. Seventy patients had confirmed YF, 69% with severe form. Mean age was 48 ± 14 years, 63 (90%) were males and 5 (7%) died. Significant electrocardiogram abnormalities were present in 52% of patients with mild/moderate form of YF (G1) and 77% of those with severe form (G2), p = 0.046. Sinus bradycardia was observed in 24% (N = 17): G1 23% versus G2 25%, p = 0.67. Among 32 patients who underwent Holter, 14 (44%) had mean HR <60 beats per minute, being 8 from G2. Echocardiogram revealed left ventricular dysfunction in 4 (6%) patients, from G2. Left ventricular wall thickening with a hyper-refringent myocardial texture suggesting infiltration was observed in 17 patients (G1 18% vs G2 27%, p = 0.55). One magnetic resonance (G2) was suggestive of myocarditis, and one necropsy revealed areas of myocardial necrosis and acute myocarditis. In conclusion, cardiac involvement was observed in patients with YF, most commonly bradycardia and myocardial hyper-refringent texture suggestive of infiltration.

Existing and potential infection risk zones of yellow fever worldwide: a modelling analysis

SummaryBackgroundYellow fever cases are under-reported and the exact distribution of the disease is unknown. An effective vaccine is available but more information is needed about which populations within risk zones should be targeted to implement interventions. Substantial outbreaks of yellow fever in Angola, Democratic Republic of the Congo, and Brazil, coupled with the global expansion of the range of its main urban vector, Aedes aegypti, suggest that yellow fever has the propensity to spread further internationally. The aim of this study was to estimate the disease's contemporary distribution and potential for spread into new areas to help inform optimal control and prevention strategies.MethodsWe assembled 1155 geographical records of yellow fever virus infection in people from 1970 to 2016. We used a Poisson point process boosted regression tree model that explicitly incorporated environmental and biological explanatory covariates, vaccination coverage, and spatial variability in disease reporting rates to predict the relative risk of apparent yellow fever virus infection at a 5 × 5 km resolution across all risk zones (47 countries across the Americas and Africa). We also used the fitted model to predict the receptivity of areas outside at-risk zones to the introduction or reintroduction of yellow fever transmission. By use of previously published estimates of annual national case numbers, we used the model to map subnational variation in incidence of yellow fever across at-risk countries and to estimate the number of cases averted by vaccination worldwide.FindingsSubstantial international and subnational spatial variation exists in relative risk and incidence of yellow fever as well as varied success of vaccination in reducing incidence in several high-risk regions, including Brazil, Cameroon, and Togo. Areas with the highest predicted average annual case numbers include large parts of Nigeria, the Democratic Republic of the Congo, and South Sudan, where vaccination coverage in 2016 was estimated to be substantially less than the recommended threshold to prevent outbreaks. Overall, we estimated that vaccination coverage levels achieved by 2016 avert between 94 336 and 118 500 cases of yellow fever annually within risk zones, on the basis of conservative and optimistic vaccination scenarios. The areas outside at-risk regions with predicted high receptivity to yellow fever transmission (eg, parts of Malaysia, Indonesia, and Thailand) were less extensive than the distribution of the main urban vector, A aegypti, with low receptivity to yellow fever transmission in southern China, where A aegypti is known to occur.InterpretationOur results provide the evidence base for targeting vaccination campaigns within risk zones, as well as emphasising their high effectiveness. Our study highlights areas where public health authorities should be most vigilant for potential spread or importation events.FundingBill & Melinda Gates Foundation.

Mosquito Soldiers: Malaria, Yellow Fever, and the Course of the American Civil War

Andrew McIlwaine Bell's study of mosquito-borne illness during the war offers a fresh approach to Civil War scholarship by suggesting that the incidence of yellow fever and malaria helped shape the events of the war. The need for such studies is great since the trend in Civil War historiography has been practically to ignore the impact of disease altogether. Adopting a natural-realist approach, Bell forges a connection between epidemiology and military history in exploring the impact of malaria and yellow fever and argues that these diseases made a crucial difference in the outcome of several campaigns. In McIlwaine's view “mosquitoes have done more to shape our history than most people realize” (116). The book is divided into seven chapters plus useful appendices. The geographical scope of the study is limited mainly to the South. The first two chapters set the stage by considering the distinctiveness of the region, including endemic southern diseases, typical remedies, and how southern diseases were understood. Both North and South, armies exploited and were vulnerable to the ravages of these diseases. There was fear among some northern commanders about fighting in the “unhealthy” south while this bolstered the confidence of Confederate commanders that the sickly season would help to disrupt their opponent's operations. But Anopheles and Aedes aegypti mosquitoes did not discriminate and southern soldiers proved equally vulnerable to the “southern diseases” challenging ideas about immunity (20). Chapter 2 examines the hazards of disease for the Civil War soldier. Soldiers on both sides frequently commented on their frustration with the mosquitoes in the south, but neither soldiers nor physicians realized that these “gallinippers” were transmitting malaria and yellow fever. In the attempt to manage yellow fever, physicians experimented with various remedies including lead, creosote, calomel, and carbolic acid which generally “did more harm than good” (32). Mosquito nets or quinine, however, proved effective against malaria. Rebel troops had difficulty procuring quinine and were forced to rely on local remedies such as turpentine plasters and various indigenous barks. As Bell demonstrates, the availability of medicine greatly affected the experience of these diseases. Owing to the effectiveness of the Union naval blockade, “Confederate soldiers and civilians suffered immensely” (112).

The Distribution of Yellow Fever in Colombia in Recent Years 1

Summary Before the anti-stegomyia campaigns in Havana, Panama and Guayaquil, epidemics of yellow fever were not uncommon in the towns and cities of Colombia along the coast and in the Magdalena valley. Following the last known outbreak in a coastal town, which occurred in Buenaventura in 1920, the country appeared to be entirely free of the disease until the unexplained appearance of urban yellow fever in Bucaramanga in 1923. After six quiet years, the disease broke out unexpectedly again in Socorro in 1929. Immunity surveys carried out by the newly discovered mouse protection test in 1931 and 1932 gave evidence that yellow fever might be endemic in some rural areas of Boyaca and Santander. As a result of a systematic study which was begun in Colombia in 1934, cases of jungle yellow fever have been found each year since in zones comprised of the departments of Antioquia, Boyaca, Caldas, Cundinamarca, Santander and Tolima, and the Intendencia del Meta. The results of an extensive immunity survey during this period confirm this distribution of yellow fever and make it appear probable that the disease has existed in recent years in other widely separated parts of the country such as the Atrato valley and the Colombian Amazon drainage. With the exception of a very small epidemic in Buenavista, Caldas, in 1937, no incidence of yellow fever transmitted by Aedes aegypti has been observed in Colombia since 1929.

The Geographical Distribution of Immunity to Yellow Fever in Man in South America 1

Summary 1. The reported incidence of yellow fever is no safe index of its occurrence in endemic zones. 2. Although visible urban and maritime outbreaks may decline and even cease entirely for a time, there is a vast, previously silent reservoir of infection in the interior of South America. 3. Yellow fever infection due to Aedes aegypti has been much more widespread in the interior of Northeast Brazil than was believed, even though this area had long been under special observation. Aegypti-transmitted fever in this area did not spontaneously disappear following the organization of antiaegypti campaigns in the principal centers of population. 4. Yellow fever endemicity, instead of being limited to the coast of Northeast Brazil as was believed, extends to all of Brazil except a few of the southern states, to Bolivia, Paraguay, Peru, Ecuador, Colombia, and Venezuela, involving many districts in which Aedes aegypti does not exist. 5. Widely varying percentages of immunes have been found in proved endemic regions, depending upon whether transmission is due to Aedes aegypti or occurs in the absence of this mosquito. 6. There is no evidence of recent yellow fever outbreaks in any of the important Pacific or Caribbean ports of South America.