Epidemiology Of Fever Research Articles

Yellow fever in Ghana: Predicting emergence and ecology from historical outbreaks.

Understanding the epidemiology and ecology of yellow fever in endemic regions is critical for preventing future outbreaks. Ghana is a high-risk country for yellow fever. In this study we estimate the disease burden, ecological cycles, and areas at risk for yellow fever in Ghana based on historical outbreaks. We identify 2387 cases and 888 deaths (case fatality rate 37.7%) from yellow fever reported in Ghana from 1910 to 2022. During the approximately 30-year periods before and after implementation of routine childhood vaccination in 1992, the reported mean annual number of cases decreased by 80%. The geographic distribution of yellow fever cases has also changed over the past century. While there have been multiple large historical outbreaks of yellow fever in regions throughout Ghana, recent outbreaks have originated in northern regions. Comparing the locations where yellow fever outbreaks have emerged, we find patterns with seasons and different ecological transmission cycles. Using an ecological niche modeling framework, we predict areas in Ghana that are similar to where prior yellow fever outbreaks have originated based on temperature, precipitation, vegetation, and human population density. We find that these predictions differ depending on the ecological cycles of outbreaks. Ultimately, these findings and methods could be used to inform further subnational risk assessments for yellow fever in Ghana and other high-risk countries.

Beyond the biting - limited impact of explicit mosquito dynamics in dengue models

Mathematical models play a crucial role in assisting public health authorities in timely disease control decision-making. For vector-borne diseases, integrating host and vector dynamics into models can be highly complex, particularly due to limited data availability, making system validation challenging. In this study, two compartmental models akin to the SIR type were developed to characterize vector-borne infectious disease dynamics. Motivated by dengue fever epidemiology, the models varied in their treatment of vector dynamics, one with implicit vector dynamics and the other explicitly modeling mosquito-host contact. Both considered temporary immunity after primary infection and disease enhancement in secondary infection, analogous to the temporary cross-immunity and the Antibody-dependent enhancement biological processes observed in dengue epidemiology. Qualitative analysis using bifurcation theory and numerical experiments revealed that the immunity period and disease enhancement outweighed the impact of explicit vector dynamics. Both models demonstrated similar bifurcation structures, indicating that explicit vector dynamics are only justified when assessing the effects of vector control methods. Otherwise, the extra equations are irrelevant, as both systems display similar dynamics scenarios. The study underscores the importance of using simple models for mathematical analysis, initiating crucial discussions among the modeling community in vector-borne diseases.

Dengue outbreaks in northern Nigeria: Evaluating the recommended Takeda vaccine and future prevention strategies.

Dengue fever, caused by the dengue virus (DENV), poses a significant public health challenge globally, with Nigeria experiencing sporadic outbreaks. A clear understanding of the dengue burden has not been achieved in Nigeria, just as in other African countries. Understanding the epidemiology and burden of dengue fever is essential for effective prevention and control strategies. This paper examines the recent dengue outbreaks in northern Nigeria, particularly in Sokoto state, and evaluates the recommended Takeda dengue vaccine (TDV) along with future prevention strategies. Despite limited surveillance and underreporting, dengue fever is endemic in Nigeria (with over 5 million cases and 5000 dengue-related deaths in 2023), with recent outbreaks indicating a growing concern. The TDV, a live attenuated tetravalent vaccine, has shown promise in preventing dengue fever, but challenges such as vaccine acceptance and accessibility need to be addressed. Global urbanization contributes to the disease's spread, which is influenced by factors such as population density, cultural beliefs, water storage practices, hygiene, and water supply accessibility. Future prevention strategies must focus on government intervention, community practices, and innovative vector control measures to mitigate the spread of DENV in Nigeria. This study will serve as a valuable reference for policymakers, researchers, and clinicians in the management and control of DENV in Nigeria and Africa as a whole.

Epidemiology of Q fever in humans in four selected regions, Spain, 2016 to 2022.

BackgroundQ fever is a bacterial zoonosis caused by Coxiella burnetii. Spain has the highest number of notified human cases in Europe. Small ruminants are a key reservoir for the pathogen, transmission from animals to humans is usually airborne.AimWe aimed at exploring temporal and spatial epidemiological patterns of sporadic and outbreak cases of Q fever in four Spanish regions with the highest number of notified cases.MethodsWe extracted data on Q fever cases in the Canary Islands, Basque Country, La Rioja and Navarre between 2016 and 2022 from the Spanish National Epidemiological Surveillance Network. We calculated standardised incidence ratios (SIR), spatial relative risks (sRR) and posterior probabilities (PP) utilising Besag-York-Mollié models.ResultsThere were 1,059 notifications, with a predominance of males aged 30-60 years. In Basque Country, La Rioja and Navarre area, 11 outbreaks were reported, while no in the Canary Islands. A seasonal increase in incidence rates was observed between March and June. In the Canary Islands, elevated sRR was seen in La Palma, Gran Canaria, Lanzarote and Fuerteventura. In Basque Country, La Rioja and Navarre area, the highest sRR was identified in the south of Biscay province.ConclusionGoats were the main source for humans in outbreaks reported in the literature. Seasonal increase may be related to the parturition season of small ruminants and specific environmental conditions. Local variations in sRR within these regions likely result from diverse environmental factors. Future One Health-oriented studies are essential to deepen our understanding of Q fever epidemiology.

Global epidemiology of severe fever with thrombocytopenia syndrome virus in human and animals: a systematic review and meta-analysis

Since the initial identification of the Severe Fever with Thrombocytopenia Syndrome (SFTS) in ticks in rural areas of China in 2009, the virus has been increasingly isolated from a diverse array of hosts globally, exhibiting a rising trend in incidence. This study aims to conduct a systematic analysis of the temporal and spatial distribution of SFTS cases, alongside an examination of the infection rates across various hosts, with the objective of addressing public concerns regarding the spread and impact of the disease. In this systematic review and meta-analysis, an exhaustive search was conducted across multiple databases, including PubMed, Web of Science, Embase, and Medline, CNKI, WanFang, and CQVIP. The literature search was confined to publications released between January 1, 2009, and May 29, 2023. The study focused on collating data pertaining to animal infections under natural conditions and human infection cases reported. Additionally, species names were unified using the National Center for Biotechnology Information (NCBI) database. The notification rate, notification death rate, case fatality rate, and infection rates (or MIR) were assessed for each study with available data. The proportions were pooled using a generalized linear mixed-effects model (GLMM). Meta-regressions were conducted for subgroup analysis. This research has been duly registered with PROSPERO, bearing the registration number CRD42023431010. We identified 5492 studies from database searches and assessed 238 full-text studies for eligibility, of which 234 studies were included in the meta-analysis. For human infection data, the overall pooled notification rate was 18.93 (95% CI 17.02-21.05) per ten million people, the overall pooled notification deaths rate was 3.49 (95% CI 2.97-4.10) per ten million people, and the overall pooled case fatality rate was 7.80% (95% CI 7.01%-8.69%). There was an increasing trend in notification rate and deaths rate, while the case fatality rate showed a significant decrease globally. Regarding animal infection data, among 94 species tested, 48 species were found to carry positive nucleic acid or antibodies. Out of these, 14 species were classified under Arthropoda, while 34 species fell under Chordata, comprising 27 Mammalia and 7 Aves. This systematic review and meta-analysis present the latest global report on SFTS. In terms of human infections, notification rates and notification deaths rates are on the rise, while the case fatality rate has significantly decreased. More SFTSV animal hosts have been discovered than before, particularly among birds, indicating a potentially broader transmission range for SFTSV. These findings provide crucial insights for the prevention and control of SFTS on a global scale. None.

Widening geographic range of Rift Valley fever disease clusters associated with climate change in East Africa

BackgroundRecent epidemiology of Rift Valley fever (RVF) disease in Africa suggests growing frequency and expanding geographic range of small disease clusters in regions that previously had not reported the disease....

Bifurcation analysis of a two infection SIR-SIR epidemic model with temporary immunity and disease enhancement

In this paper we study a two infection SIR-SIR compartmental model, considering biological features described in dengue fever epidemiology. Due to a progressive loss of protective antibodies there is waning immunity in the first infection stage and disease enhancement or protection effects by the second infection stage. Bifurcation analysis reveals two codim-2 bifurcations as organizing centers. The unfolding of a cusp bifurcation describes the transition of the disease-free equilibrium into an endemic equilibrium by varying a parameter. These equilibria allow an analytical solution with explicit expressions which allow for a full geometrical interpretation of the occurring bifurcations related to stationary dynamics. A Bogdanov-Takens point is the starting point in the parameter space where oscillatory endemic dynamics occurs including a homoclinic connection. These findings bring additional insights on biological mechanisms able to generate rich and complicated dynamical behavior in simple epidemic models that are, so far, largely unexplored.

Changing trends in Japanese spotted fever epidemiology in Shimane, Japan: A two-decade retrospective study with emphasis on the COVID-19 pandemic era

IntroductionThe objective of this study is to evaluate the epidemiological characteristics of Japanese Spotted Fever (JSF) cases reported through the National Epidemiological Surveillance of Infectious Disease (NESID) system in Shimane Prefecture, Japan, from 2000 to 2022, encompassing the periods before and during the COVID-19 pandemic period. MethodsA retrospective analysis was conducted on JSF cases reported to the NESID system in Shimane Prefecture between 2000 and 2022. Population data were obtained from the Statistical Information of Shimane. Poisson regression analysis was employed to examine the relationship between the annual prevalence rate of JSF and the COVID-19 pandemic. ResultsA total of 301 JSF cases were analyzed during the study period. Even the pre-COVID-19 pandemic period, a gradual and significant increase in the prevalence rate was observed (prevalence rate = 1.03, 95% CI: 1.01–1.05; p = 0.01), and a rapid increase was noted since 2020 (prevalence rate = 1.57, 95% CI: 1.39–1.78; p < 0.01). The slope during the pre-COVID-19 pandemic period was estimated to have significantly increased (p < 0.01). ConclusionsOur findings suggest that while the prevalence rate of JSF had exhibited a slight increase in the years preceding the COVID-19 pandemic, it demonstrated a more significant increase following the pandemic in Shimane Prefecture. JSF has increased since 2020 and may be linked to COVID-19 pandemic. The COVID-19 pandemic has had a substantial impact on global health, underscoring the importance of investigating the prevalence of specific infectious diseases and other health-related indicators to accurately assess the pandemic's impact.

Epidemiology of typhoid fever in the Philippines during the last six decades from 1960-2019: a profile and its trend

Regardless of the numerous reviews and publications on typhoid fever in the Philippines, it continues to be an issue regarding public health. Using data obtained from the Philippine Health Statistics (PHS), this study examined trends in typhoid fever mortality across an interval of six decades in the Philippines. The mortality and morbidity rates of typhoid fever were analyzed to discover trends of change for each year, age group, sex, and area. The Microsoft Excel software tool became used for all data analysis. The results show a decrease in typhoid fever fatality rates in the Philippines over the previous year. In terms of sex-specific deaths, males outnumbered females. The individuals aged 70 and older have the highest death rates when it comes to age-specific mortality rates. In the Philippines, Region I also has the highest mortality rate from typhoid fever. For instance, the Autonomous Region of Muslim Mindanao (ARMM) has the lowest mortality rate from typhoid fever. The highest average morbidity rate is in the Cordillera administrative region (CAR), while the lowest is in Region IVB. To eliminate typhoid fever in the next few years and to completely combat typhoid fever throughout the years, educational campaign awareness or intimate knowledge must be conducted locally and globally.

Epidemiology of Hemorrhagic Fever with Renal Syndrome and Host Surveillance in Zhejiang Province, China, 1990-2021.

Hemorrhagic fever with renal syndrome (HFRS) is caused by hantaviruses (HVs) and is endemic in Zhejiang Province, China. In this study, we aimed to explore the changing epidemiology of HFRS cases and the dynamics of hantavirus hosts in Zhejiang Province. Joinpoint regression was used to analyze long-term trends in the incidence of HFRS. The comparison of animal density at different stages was conducted using the Mann-Whitney Test. A comparison of HV carriage rates between stages and species was performed using the chi-square test. The incidence of HFRS shows a continuous downward trend. Cases are widely distributed in all counties of Zhejiang Province except Shengsi County. There was a high incidence belt from west to east, with low incidence in the south and north. The HFRS epidemic showed two seasonal peaks in Zhejiang Province, which were winter and summer. It showed a marked increase in the age of the incidence population. A total of 23,073 minibeasts from 21 species were captured. Positive results were detected in the lung tissues of 14 rodent species and 1 shrew species. A total of 80% of the positive results were from striped field mice and brown rats. No difference in HV carriage rates between striped field mice and brown rats was observed (χ2 = 0.258, p = 0.611).

Epidemiology and Outcomes of Crimean-Congo Hemorrhagic Fever in Afghanistan: A Review of 2010–2019

Background: The study investigates the recent surge in Crimean-Congo Hemorrhagic Fever (CCHF) cases in Afghanistan, a high-risk viral disease transmitted through tick bites and livestock, and aims to identify patterns of the increase and offer prevention strategies. Methods: A systematic review of all scholarly articles published on CCHF in Afghanistan between 2010 and 2019 was conducted using a comprehensive and rigorous search strategy using the PubMed database. The quality of the included studies was assessed using the Newcastle-Ottawa Scale and the Cochrane Risk of Bias Tool. Results: During the study period, 1537 suspected cases of CCHF were reported in Afghanistan, with the highest number and deaths in the western region. The majority of cases were male, aged 16-84, and involved in animal husbandry, agriculture, and healthcare workers, with a 2:1 male-to-female ratio. The majority of cases were aged 16-84. Conclusion: This study highlights the need for effective measures to prevent CCHF transmission in Afghanistan, such as education, improved animal management, and infection control in hospitals and laboratories, to reduce outbreak risks and enhance public health.

Detection and seroprevalence of Q fever infection in dairy goats in Besut district, Malaysia.

This study aimed to investigate the seroprevalence of Q fever and its association with age and gender among Saanen dairy goats in Malaysia. One hundred dairy goats (n = 100) aged 6 months to 6 years were randomly selected, and blood samples were collected for serological analysis using the enzyme-linked immunosorbent assay technique. The results revealed a seropositive rate of 70% among the goats, with medium-positive titers being the most common. The prevalence of Q fever varied among different age groups, with higher rates observed in adult goats aged between 5 and 6 years. Gender analysis showed that males had a higher positive rate (p < 0.05) of Q fever compared to females. These findings strongly indicate the presence of Coxiella burnetii in the dairy goat population and highlight the importance of implementing biosecurity measures and control strategies to prevent further transmission of this disease. This research has contributed to a better understanding of Q fever epidemiology and provides insights for effective control and prevention strategies in dairy goat populations.

Epidemiology and clinical characteristics of hemorrhagic fever with renal disease syndrome in the Autonomous Province of Vojvodina

Introduction. The aim of this study was to determine the epidemiological and clinical characteristics of hemorrhagic fever with renal syndrome in Vojvodina from 2008-2015 and to examine the factors associated with acute renal failure and hemorrhagic syndrome. Material and Methods. Data were extracted from medical records spanning 2008 to 2015, including demographic, epidemiological, clinical, and laboratory findings at hospital admission, as well as the course and outcome of treatment. The study investigated the correlation between disease incidence and climate, focusing on acute renal failure, its risk factors, the incidence of hemorrhagic syndrome, and factors influencing hospital stay duration. Results. The highest incidence for hemorrhagic fever with renal syndrome was recorded in 2014, with a rate of 0.5 per 100.000 inhabitants. Acute renal failure was observed in 40% of patients, while mild manifestations of hemorrhagic syndrome were noted in 46.7% of cases. Factors contributing to acute renal failure included lumbar pain (p=0.005), creatinine concentrations (p=0.011), and Simplified Acute Physiology score (p=0.013). The average length of hospitalization was 10 days (range 7-13 days) and was correlated with increased leukocytosis (p=0.028; ?=0.566), higher C-reactive protein values (p=0.014; ?=0.686), lower serum sodium levels (p=0.009; ?=0.772), higher serum creatinine concentrations (p=0.002; ?=0.742), the Sequential Organ Failure Assessment score (p=0.013; ?=0.612) and the Simplified Acute Physiology score (p=0.023; ?=0.582). Conclusion. Climatic factors are associated with the incidence of hemorrhagic fever with renal syndrome. The overall outcome of the disease was favorable.

An insight into the history &amp; epidemiology of Chikungunya fever in India

An insight into the history &amp; epidemiology of Chikungunya fever in India

Seroprevalence and Co-Circulation of Rift Valley Fever Virus and West Nile Fever Virus in Livestock Population of Afar Region, Northeast Ethiopia.

The distribution, epidemiology, and socioeconomic impact of Rift Valley fever (RVF) and West Nile (WN) viruses are poorly known in areas of sub-Saharan countries like Ethiopian pastoral region. The human and livestock density in the area has increased greatly in recent years, but little work has been done on arboviral diseases and their potential impact on human and livestock health. The aim of this study was to detect the circulation of zoonotic arboviruses such as Rift Valley fever virus and West Nile viruses in the livestock population and to estimate seroprevalence in Afar pastoral area northeast Ethiopia. Cross-sectional serological survey was carried out in 736 serum samples from which cattle (224), camel (155), goats (121), sheep (144), and donkeys (92) were tested for the presence of anti-RVFV and anti-WNV IgG using a competitive enzyme-linked immunosorbent assay (c-ELISA) in two purposively selected districts of the Afar region. The present study revealed a 9.1% (95% CI = 8.86-9.29) seroprevalence of co-circulation of RVF and WNV. High 32/155 (20.7%) seroprevalence of co-circulation was seen in camels, followed by goat 14/121 (11.6%), cattle 16/224 (7.14%), and sheep 5/144 (3.5%), respectively, and higher 41/421 (9.7%) seroprevalence of co-circulation was observed in Amibara district than Haruka district. Camels were seven times (OR: 7.016, 95% CI = 2.639-18.653) more likely to be seropositive for the co-circulation than sheep (p ≤ 0.001). Livestock herds found in Amibara district were 1.2 times (OR: 1.165, 95% CI = 0.680-1.996) more likely to be seropositive for RVFV infection than those in Haruka areas. Given the co-occurrence of RVFV and WNV circulations, along with often suboptimal human and animal health surveillance in many similar areas' attention should be given. Investigation of the potential socioeconomic and health impacts of zoonotic arbovirus infections in such areas is crucial. Since both RVFV and WNFV are transmitted through a mosquito vector, avoiding mosquito bites is the primary method of prevention.

The Spatiotemporal Epidemiology of African Swine Fever in the Mekong Delta and the Review of Vaccine Development in Vietnam

The Spatiotemporal Epidemiology of African Swine Fever in the Mekong Delta and the Review of Vaccine Development in Vietnam

Epidemiology of Severe Fever with Thrombocytopenia Syndrome in Dogs and Cats in Taiwan.

Severe Fever with Thrombocytopenia Syndrome (SFTS), caused by the SFTS Virus (SFTSV), is a global health threat. SFTSV in Taiwan has only been reported in ruminants and wild animals. Thus, we aimed to investigate the infection statuses of dogs and cats, the animals with closer human interactions. Overall, the SFTSV RNA prevalence was 23% (170/735), with dogs showing a 25.9% (111/429) prevalence and cats at 19.3% (59/306) prevalence. Noticeably, the prevalence in stray animals (39.8% 77/193) was significantly higher than in domesticated ones (17.2%, 93/542). Among the four categories analyzed, the highest SFTSV prevalence was found in the stray dogs at 53.9% (120/193), significantly higher than the 24.2% prevalence noted in stray cats. In contrast, domesticated animals exhibited similar prevalence rates, with 17.1% for dogs and 17.2% for cats. It is noteworthy that in the domesticated animal groups, a significantly elevated prevalence (45%, 9/20) was observed among cats exhibiting thrombocytopenia compared to those platelet counts in the reference range (4.8%, 1/21). The high infection rate in stray animals, especially stray dogs, indicated that exposure to various outdoor environments influences the prevalence of infections. Given the higher human interaction with dogs and cats, there is a need for proactive measures to reduce the risk associated with the infection of SFTSV in both animals and humans.

Genotyping and phylogenetic analysis of Coxiella burnetii in domestic ruminant and clinical samples in Iran: insights into Q fever epidemiology

Coxiella burnetii, a zoonotic pathogen, is the causative agent of Q fever, an endemic disease in Iran. However, there is currently a lack of available data on the genotypes of C. burnetii in the country. Here, we typed 26 C. burnetii isolates detected in milk, abortion, cotylodon, and cardiac valve samples from various geographical areas and hosts (7 cattle, 8 goats, 10 sheep, and 1 human) using Multilocus Variable Number Tandem Repeat Analysis (MLVA/VNTR) with five loci:ms24, ms27, ms28, ms33, and ms34. As IS1111 was observed to be spontaneously inserted in locus ms23 across all of our examined C. burnetii samples, five loci were employed for MLVA/VNTR genotyping. Among the 26 C. burnetii strains, 22 distinct genotypes (A–V) were identified in the discriminative loci. In silico analysis categorized Iranian C. burnetii strains into five genomic groups along with seven singletons, representing 11 exiting clonal complexes worldwide. Clusters 10 and 11 exclusively consisted of Iranian samples. These findings revealed high genotyping diversity among C. burnetii isolates in Iran. The genotypes circulating in Iran differed significantly from those found in other regions worldwide. To gain a comprehensive understanding of Q fever epidemiology in Iran, it is crucial to conduct large-scale studies that assess the distribution of C. burnetii genotypes across different geographical areas, hosts, and sources.

Hemorrhagic fever with renal syndrome and leptospirosis: Differential diagnosis

Hemorrhagic fever with renal syndrome and leptospirosis have similarities and differences in the clinical picture. Fever, intoxication, pronounced kidney damage and hemorrhagic syndrome are observed in both infections. The course of these diseases may be complicated by the development of infectious-toxic shock, acute renal failure, disseminated intravascular coagulation. Clinical manifestations of the syndrome of jaundice and meningitis may be observed in leptospirosis, but are not characteristic of hemorrhagic fever with renal syndrome. In leptospirosis, in contrast to hemorrhagic fever with renal syndrome, liver failure may develop. Infection with these diseases often occurs during a stay in a forest, in a holiday home, in rural areas. The natural foci of these infections may be located on the same territories or border each other, which also complicates the differential diagnostics. The article provides information on the etiology, epidemiology, geographical distribution, pathogenesis, pathological anatomy, clinical picture and diagnostics of hemorrhagic fever with renal syndrome and leptospirosis. Based on these data, the pathophysiological, clinical and laboratory aspects of the differential diagnosis between these diseases are analyzed in detail.

Symmetry in a multi-strain epidemiological model with distributed delay as a general cross-protection period and disease enhancement factor

Important biological features of viral infectious diseases caused by multiple agents with interacting strain dynamics continue to pose challenges for mathematical modelling development. Motivated by dengue fever epidemiology, we study a system of Integro-Differential Equations (IDE) considering strain structure of pathogens. Knowing that complex dynamics observed in dengue models are driven by the combination of two biological features, the temporary cross-immunity (TCI) and disease enhancement via the antibody-dependent enhancement process (ADE), our IDE system incorporates the TCI with a general time delay term, and the ADE effect by a constant factor to differentiate the susceptibility of individuals experiencing a primary or a secondary infection. Aiming at analysing the effect of the symmetry on dengue serotypes in the IDE framework, a detailed qualitative analysis of the model is performed and the instability of the coexistence steady state is shown using the perturbation theory approach. Numerical simulations identify the bifurcation structures and confirm the stability analysis. Results for the symmetric and asymmetric models are discussed.