Field Epidemiological Investigations Research Articles

Infection Tracing and Virus Genomic Analysis of Two Cases of Human Infection with Avian Influenza A(H5N6) - Fujian Province, China, April-May 2024.

Global human cases of zoonotic influenza A(H5N6) have increased significantly in recent years, primarily due to widespread circulation of clade 2.3.4.4b virus since 2020. Concurrent with this trend, sporadic human infections with clade 2.3.4.4h H5N6 avian influenza virus continue to occur. The high mortality rate associated with H5N6 virus infections has emerged as a critical public health concern. Through comprehensive field epidemiological investigations and laboratory analyses, we identified the infection sources for these cases and conclusively ruled out human-to-human transmission. Genetic analyses revealed that while the virus maintains its avian host tropism, it has acquired mutations that may enhance human receptor binding affinity, viral replication capacity, pathogenicity, and neuraminidase inhibitor resistance. The ongoing viral mutations increase the potential for H5 subtype avian influenza viruses to overcome species barriers and cause human epidemics. Enhanced surveillance strategies incorporating advanced technologies, such as metagenomic sequencing, are essential for early risk detection and management. Special attention should be directed toward cancer patients and immunocompromised individuals, who demonstrate increased susceptibility to avian influenza virus infections and require targeted prevention and control measures.

Study on the index system for field epidemiological investigations of viral respiratory infectious diseases

The study used the Delphi method to conduct two rounds of expert consultations involving 23 experts nationwide, aiming to establish the comprehensive index system for field epidemiological investigations of viral respiratory infectious diseases and determine the weights assigned to each index through the hierarchical analysis. Both rounds of consultation witnessed a 100% participation rate among all experts, with a coefficient of authority (Cr) reaching 0.89. The Kendall's W coefficients for assessing the importance and feasibility in both rounds were 0.108, 0.234, 0.439 and 0.427, respectively. Finally, an index system consisting of seven first-level indicators, 18 second-level indicators, and 36 third-level indicators was constructed for the technical guidelines governing field epidemiological investigations into viral respiratory infectious diseases, and the weight of each indicator was established. The index system constructed in this study has a high degree of scientificity, reliability and operability, but it still needs to be further adjusted and improved in combination with the epidemiological characteristics of viral respiratory infectious diseases.

Ethion food poisoning outbreak in Pereira, Colombia, 2022

Introduction Ethion is an organophosphate used as an acaricide and insecticide, that is restricted worldwide. In Colombia, pesticide poisoning is the third most common cause of chemical intoxication. On 9 October 2022, an outbreak of ethion poisoning occurred in Pereira. The aim of this study was to describe the clinical and epidemiological characteristics of the outbreak. Methods This is a descriptive study of an outbreak of organophosphate poisoning. The onset of symptoms occurred on 9 October 2022, following the consumption of empanadas. Information was collected on sociodemographic characteristics and clinical manifestations, as well as from paraclinical examinations. Data were obtained from clinical histories, field epidemiological investigations, and inspection visits. Food samples were collected for analysis by gas chromatography-mass spectrometry. Attack rates, proportions, and measures of central tendency, dispersion, and position were calculated. Results The case definition was met by 37 individuals with a median age of 30 years; all presented with muscarinic symptoms, 29 patients presented with nicotinic symptoms, and 20 patients presented with neurological symptoms. Males were the most affected (57%), and the most common time of symptom onset was 10:00 am. Twenty-three patients (62%) required intensive care unit admission, of whom 14 (38%) required mechanical ventilation. No deaths were reported. Erythrocyte acetylcholinesterase activity was reduced in all patients. Ethion was detected in mass-prepared maize and empanadas at concentrations greater than 0.1 mg/kg. The consumption of empanadas was identified as the common source. Discussion In Colombia, pesticide poisonings are the third most common type of poisoning caused by chemical substances reported to the National Health Institute through the National Public Health Surveillance System. In the present outbreak, ethion was in empanadas, likely due to contamination of cooking oil. Conclusions We describe a large ethion-contaminated food poisoning outbreak reported in Colombia. The main symptoms were muscarinic, and the main treatment measures employed were atropine and respiratory support. Increased awareness of pesticide poisoning and training for food handlers are needed.

Application of virtual simulation technology in epidemiology education: a systematic review

Objective: To systematically review the progress, advantages, disadvantages, precautions and future trends of virtual simulation technology used in epidemiology teaching. Methods: A systematical literature retrieval was conducted by using PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang Data and VIP Paper Check System with key words of epidemiology, teaching and virtual simulation, and the literatures included were screened and classified with narrative integration method. Chinese virtual simulation teaching platforms were used to select the literatures about existing epidemiology virtual simulation teaching projects for integration and analysis. Results: A total of 22 articles were included (7 in Chinese and 15 in English), most of which were teaching projects for students majoring in Public Health. We also found 24 national first-class courses and 21 provincial first-class courses in virtual simulation of epidemiology in China. The application of virtual simulation technology in epidemiology education is still in its infancy, and the interaction degree is mostly moderate. It is mainly used in three scenarios: improving the visualization degree of complex concepts and structures, training the operational skills through low-risk and low-cost virtual environment, serving as an effective supplement to the teaching of epidemiological field investigation and response to public health emergencies. In terms of effect, it is conducive to students' understanding of epidemiology related phenomena and principles, and has the advantages of breaking through time and space constraints, reducing teaching costs and risks, improving students' attention and satisfaction and so on. However, it also faces the lack of foundation in the initial stage, and some students have problems such as psychological and physiological discomfort. In the future, we need to optimize the development process, program design and so on. At the same time, we should conduct more in-depth research on cost calculation, effect evaluation and curriculum integration. Conclusions: The application of virtual simulation technology in epidemiology education is an important part of training high-level applied public health talents. We encourage to actively carry out virtual simulation teaching in epidemiology, and train public health talents with Chinese characteristics.

The role of health mediation in investigation of Hantavirus cases among informal settlements inhabitants of Cayenne area, French Guiana, 2022-2023.

In 2022, four severe cases of Hantavirus pulmonary syndrome (HPS) were reported in patients from informal settlements around Cayenne, the main city in French Guiana. Regional Health Agency (RHA) was commissioned by the French Public Health Agency to estimate the seroprevalence of Hantavirus infections in the neighborhoods of confirmed cases of HPS. RHA then commissioned the French Red Cross (FRC) mobile public health team, providing support in environmental health issues to the population living in informal settlements by health mediators, to facilitate the investigation. The objective of this study was to describe the health mediators' activities set up to improve the efficiency of the investigation. The health mediators' team was specifically trained by virologist and infectiologist specialized in HPS. They helped the investigating team and health workers at various steps of the investigation. These interventions are then described in the results section. The investigation took place between Nov. 2022 and March 2023 in three neighborhoods. During the pre-investigation activities, the mediators raised awareness about HPS of 343 people, among whom 319 (93%) planned to participate in the investigation. Altogether, 274 people finally participated in the investigation, including, i.e., 30.8% of the estimated population living in the three concerned settlements. The global proportion of patients with positive IgG anti-Hantavirus was 5.1%. The health mediators team supported the following steps: preliminary meetings and training modules, identification of resource persons, field visits and awareness and information campaigns (pre-investigation); on field data collection in informal settlements (per-investigation) and communication of individual results, public feedback meeting (post-investigation). The involvement of mediators was probably a factor in the success of the public health response to socially vulnerable people living in the investigated neighborhoods. The preliminary prevention activities helped to raise awareness of the health risk and to enroll participants. Health mediation and outreach activities seem relevant tools of epidemiological field investigations in diseases affecting inhabitants of informal settlements.

Diagnosing and reintegrating traceability of infectious diseases via metagenomic next-generation sequencing: Study of a severe case of Rickettsia japonica infection

BackgroundIn this study, we present a case of Japanese spotted fever (JSF) caused by Rickettsia japonica and use this case to investigate the process of diagnosing and reintegrating traceability of infectious diseases via metagenomic next-generation sequencing (mNGS). MethodsFrom data relating to epidemiological history, clinical and laboratory examinations, and mNGS sequencing, a diagnosis of severe JSF was concluded. ResultsA detailed field epidemiological investigation discovered parasitic Haemaphysalis longicornis from a host animal (dog) in the domicile of the patient, within which R. japonica was detected, along with a diverse array of other potentially pathogenic microorganisms that could cause other infectious diseases. ConclusionThe mNGS provided an efficient method to diagnose JSF infection. This methodology could also be applied to field epidemiological investigations to establish the traceability of infectious diseases.

Development and application of photocatalytic coating for roadside NOx mitigation in Hong Kong

A facile chemical method for the development of photocatalytic coating products was proposed based on practical application perspective for the Hong Kong roadside nitrogen oxides (NOx) mitigation. TiO2-based photocatalytic coating PC-C film with crystallized size of around 5–6 nm was synthesized with the peptization of H2O2. The PC-C coating possesses a super-hydrophilicity surface and is proven to have a NOx degradation rate of 46.8% with an optimum pH level of 7. In addition, the PC-C coating presents a promising photocatalytic NOx degradation compared with other commercially available coating products and P25 when applied on two building materials of poly-methyl methacrylate (PMMA) and concrete surface. A weather resistance simulation and a 180-day on-site field trial were carried out the attenuation effects of photocatalytic coating applied in outdoor exposure. Based on epidemiological estimation and field investigation, hospital admissions for respiratory diseases (HARD) and mortality cases (MC) could be reduced with the application of PC-C coating along the street canyon. This work demonstrates the feasibility of air pollution control measures for the local roadside NOx using photocatalytic technology, offering promising health benefits with environmental remediation.

Whole-Genome Sequencing and Epidemiological Investigation of Tuberculosis Outbreaks in High Schools in Hunan, China.

BackgroundTuberculosis (TB) seriously threatens individual and public health. Recently, TB outbreaks in schools have been reported more frequently in China and have attracted widespread attention. We reported three TB outbreaks in high schools in Hunan Province, China.MethodsWhen a tuberculosis patient was reported in a school, we carried out field epidemiological investigations, including tuberculin skin testing (TST), chest X-ray (CXR) and laboratory test for all close contacts, and whole-genome sequencing (WGS) analyses to understand the transmission patterns, the causes and the risk factors for the outbreaks, thereby providing a foundation for the control of TB epidemics in schools.ResultsA total of 49 students with TB patients were identified in the three schools where TB outbreaks occurred, including nine patients in School A, 14 patients in School B, and 26 patients in School C. In Schools A, B and C, the putative attack rates in the classes of the index case were 13.8% (8/58), 7.6% (5/66), and 40.4% (21/52), while the putative attack rates of expanding screening in the school were 0.3% (1/361), 0.2% (9/3955), and 0.2% (5/2080), respectively. Thirteen patients had patient delay, with a median delay interval of 69 days (IQR 30.5–113 days). Twelve patients had a healthcare diagnostic delay with a median delay interval of 32 days (IQR 24–82 days). Phylogenetic analysis of culture-positive patients revealed that most of them shared a small genetic distance (≤12 SNPs), with three separate genetic clusters (including one MDR-TB genomic cluster), indicating the recent transmission of Mycobacterium tuberculosis strains.ConclusionThis combination of field investigation and WGS analysis revealed the transmission of three TB outbreaks in schools. Reinforced implementation is needed to improve timely case finding and reduce diagnosis delay in routine TB control in the school population.

Bayesint: A Python Package for Calculating Bayesian Credible Intervals of Ratios of Beta Distributions

We present <em>bayesint</em>, a Python package for calculating Bayesian credible intervals for ratios of two independent beta distributions such as are used when considering binomial data. Such data could be found in counts of events in medical diagnostic tests, case-control studies, and field epidemiological investigations, among other applications. The package contains general functions providing the expression of the density and distribution of the ratio and two functions for calculating the equal-tailed and highest posterior density credible intervals. The package is intended for use with 2×2 contingency tables. We introduce <em>bayesint</em> by comparing two groups in a contingency table through calculating the relative risk of cholera, showcasing its use in a novel context.

Live poultry feeding and trading network and the transmission of avian influenza A(H5N6) virus in a large city in China, 2014–2015

ObjectivesTo understand the transmission mechanisms of the avian influenza A(H5N6) virus. MethodsThis study explored the live poultry feeding and trading network (LPFTN) around Changsha city, China. Field epidemiological investigations were performed in Changsha to investigate the LPFTN with the environmental samples systematically collected during 2014–2015 to monitor and analyze the spread of the A(H5N6) virus. Two surveillance systems were also applied to find possible human cases of A(H5N6) infection. ResultThe information of all the 665 live poultry farming sites, five wholesale markets, and 223 retail markets in Changsha was collected to investigate the LPFTN. Moreover, about 840 environmental samples were systematically collected from the LPFTN during 2014–2015 to monitor the spread of the A(H5N6) virus, with 8.45% (71/840) positive for the N6 subtype. Furthermore, the full genome sequences of 10 A(H5N6) viruses detected from the environmental samples were obtained, which were then characterized and phylogenetically analyzed with the corresponding gene segments of the A(H5N6) virus obtained from GenBank, to determine the source of human infection. ConclusionIt was demonstrated that the LPFTN provided a platform for the H5N6 transmission, and formed an infectious pool for the spread of the virus to humans.

The impact of COVID-19 first wave on long term care facilities of an Italian Province: an historical reference

The coronavirus disease 2019 (COVID-19) pandemic will leave a profound imprint in the collective memory of humanity. In Italy, Long-Term Care Facilities (LTCFs) have seen a disproportionally high number of deaths during and the COVID-19 pandemic and, certainly, they may be considered as its epicenter. Aiming to leave a symbolic mark of what the pandemic did in these care settings, we report on an outbreak in a single LTCF where, 53 out of 64 residents, resulted infected. Our narration is based on an epidemiological field investigation together with a calendar of passages through the stages of disease in the infected population. We found an age-gradient in all clinical and epidemiological variables explored such as symptoms onset, illness severity, recovery from symptoms and deaths. According to the disease staging, 26 (49%) were asymptomatic; 9 (17%) had a mild disease; 7 (13%) a moderate stage and 11 (21%) a severe illness severity of whom 10 died. For a more comprehensive description of the impact of the pandemic on LTCFs, we compared the standard mortality ratio (SMR) in the first six months of 2020 to that of 2018 and 2019 in all the 34 facilities of the Vicenza province. Overall, there was a SMR higher 60% than the equivalent period of the previous years.

A Genome Epidemiological Study of SARS-CoV-2 Introduction into Japan.

After the first case of coronavirus disease 2019 (COVID-19) in Japan on 15 January 2020, multiple nationwide COVID-19 clusters were identified by the end of February. The Japanese government focused on mitigating the emerging COVID-19 clusters by conducting active nationwide epidemiological surveillance. However, an increasing number of cases continued to appear until early April 2020, many with unclear infection routes and no recent history of travel outside Japan. We aimed to evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequences from the COVID-19 cases that appeared until early April 2020 and to characterize their genealogical networks in order to demonstrate possible routes of spread in Japan. Nasopharyngeal specimens were collected from patients, and reverse transcription-quantitative PCR tests for SARS-CoV-2 were performed. Positive RNA samples were subjected to whole-genome sequencing, and a haplotype network analysis was performed. Some of the primary clusters identified during January and February 2020 in Japan descended directly from the Wuhan-Hu-1-related isolates from China and other distinct clusters. Clusters were almost contained until mid-March; the haplotype network analysis demonstrated that the COVID-19 cases from late March through early April may have created an additional large cluster related to the outbreak in Europe, leading to additional spread within Japan. In conclusion, genome surveillance has suggested that there were at least two distinct SARS-CoV-2 introductions into Japan from China and other countries.IMPORTANCE This study aimed to evaluate the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genome sequences from COVID-19 cases and to characterize their genealogical networks to demonstrate possible routes of spread in Japan. We found that there were at least two distinct SARS-CoV-2 introductions into Japan, initially from China and subsequently from other countries, including Europe. Our findings can help understand how SARS-CoV-2 entered Japan and contribute to increased knowledge of SARS-CoV-2 in Asia and its association with implemented stay-at-home/shelter-in-place/self-restraint/lockdown measures. This study suggested that it is necessary to formulate a more efficient containment strategy using real-time genome surveillance to support epidemiological field investigations in order to highlight potential infection linkages and mitigate the next wave of COVID-19 in Japan.

Quantitative Outcomes of a One Health Approach to Investigate the First Outbreak of African Swine Fever in the Republic of Sierra Leone

African swine fever (ASF) outbreaks have been reported in Sub-Saharan countries, including West Africa states, but has never been notified in the Republic of Sierra Leone. This is the first report describing field epidemiological and laboratory investigations into the outbreak of fatal pig disease in western rural and urban districts, Freetown. A preliminary finding indicated that pigs exhibited clinical and necropsy signs suggestive of ASF. Serological (ELISA) and molecular (qRT-PCR) methods used to confirm and investigate the outbreak yielded three positive results for the ASF antibody and all negative for Swine flu; thus, confirming ASF as the etiology agent.

Survey of Traveler's Diarrhea: Epidemiology and Testing Reveal the Source.

Objective To understand the causes and transmission routes of, as well as risk factors, for a Salmonella outbreak in a tour group. Method A retrospective cohort design was used to conduct an epidemiological field investigation. Real-time fluorescent quantitative PCR, bacterial culture, and serological identification methods were used for pathogen detection and identification. Result There were 7 cases of illness, and the attack rate was 46.67%. The onset date was concentrated on May 9 and 10. All cases were found in the tour group, and no cases occurred in the nontour group. The results of this retrospective cohort study showed that the consumption of boiled eggs for breakfast on May 9 was a common factor (R2 = 6.67, P=0.023). Salmonella enteritidis was identified from the patients' stool and vomit. Conclusion The food poisoning epidemic was caused by Salmonella enteritidis. In the summer and autumn, attention should be paid to preservation, processing, and cooking of food to avoid bacterial contamination. To prevent sickness, travelers should know the disease prevalence at their destinations in advance.

Measles outbreak from Hong Kong International Airport to the hospital due to secondary vaccine failure in healthcare workers.

To report an outbreak of measles with epidemiological link between Hong Kong International Airport (HKIA) and a hospital. Epidemiological investigations, patients' measles serology, and phylogenetic analysis of the hemagglutinin (H) and nucleoprotein (N) genes of measles virus isolates were conducted. In total, 29 HKIA staff of diverse ranks and working locations were infected with measles within 1 month. Significantly fewer affected staff had history of travel than non-HKIA-related measles patients [10 of 29 (34.5%) vs 28 of 35 (80%); P < .01]. Of 9 airport staff who could recall detailed exposure history, 6 (66.7%) had visited self-service food premises at HKIA during the incubation period, where food trays, as observed during the epidemiological field investigation, were not washed after use. Furthermore, 1 airport baggage handler who was admitted to hospital A before rash onset infected 2 healthcare workers (HCWs) known to have 2 doses of MMR vaccination with positive measles IgG and lower viral loads in respiratory specimens. Infections in these 2 HCWs warranted contact tracing of another 168 persons (97 patients and 71 HCWs). Phylogenetic comparison of H and N gene sequences confirmed the clonality of outbreak strains. Despite good herd immunity with overall seroprevalence of >95% against measles, major outbreaks of measles occurred among HKIA staff having daily contact with many international pssengers. Lessons from severe acute respiratory syndrome (SARS) and measles outbreaks suggested that an airport can be a strategic epidemic center. Pre-exanthem transmission of measles from airport staff to HCWs with secondary vaccine failure poses a grave challenge to hospital infection control.

Epidemiological Investigation of Acute Gastroenteritis in a Residential Campus Area of Delhi, India

Background: This report is about the investigation of an outbreak of acute gastroenteritis that claimed two human lives and left 180 people affected within one week of its outbreak in a residential campus area in Delhi, India in the month of June 2013. The study was conducted to find out the causes of acute gastroenteritis outbreak and to suggest preventive and control measures. Methods: A cross sectional study was designed and a pre-tested pre-designed epidemiological case sheet was used and a total of 180 cases of acute gastroenteritis were interviewed. Contribution by ecological factors was also assessed. Stool and water samples were also collected. Results: Out of 14000 inhabitants, 180 people suffered from similar complaints of acute gastroenteritis. Males and females were almost equally affected although people in the age group 15 - 44 completed years, 88 (48.8%) and those living in type I quarters, 108 (60%) were affected most. Epidemic curve with single peak was obtained. Environmental surveillance revealed breakage of drinking water pipelines and mixing of drinking water with sewage water near type I quarters. Out of 14 stool samples collected, one was positive for Vibrio cholerae (ogawa serotype). Conclusion: The present study reflected the possible contamination drinking water with sewage water in outbreak of gastroenteritis. By employing simple epidemiological field investigation, the outbreak was brought under control.

Interconnected clusters of invasive meningococcal disease due to Neisseria meningitidis serogroup C ST-11 (cc11), involving bisexuals and men who have sex with men, with discos and gay-venues hotspots of transmission, Tuscany, Italy, 2015 to 2016

In 2015 an increased incidence of invasive meningococcal disease due to serogroup-C (MenC) occurred in Tuscany, Italy. This led the Regional Health Authority of Tuscany to implement a reactive immunisation campaign and to launch an epidemiological field investigation aiming to address targeted immunisation interventions. In 2011–14, 10 MenC cases had been reported compared with 62 cases in 2015–16. The case fatality rate was 21% (n = 13) and 51 cases (82.3%) were confirmed as C:P1.5–1,10–8:F3–6:ST-11(cc11). Overall, 17 clusters were recognised. Six discos and four gay-venues were found to have a role as transmission-hotspots, having been attended by 20 and 14 cases in the 10 days before symptoms onset. Ten and three cases occurred, respectively, among men who have sex with men (MSM) and bisexual individuals, who were involved in 11 clusters. In addition, heterosexual cases (n = 5) attending gay-venues were also found. Secondary cases were not identified. Molecular typing indicated close relationship with MenC clusters recently described among gay, bisexual and other MSM in Europe and the United States, suggesting a possible international spread of the serogroup-C-variant P1.5–1,10–8:F3–6:ST-11(cc11) in this population-group; however, epidemiological links were not identified. In December 2016, a targeted vaccination campaign involving discos and lesbian, gay, bisexual, and transgender (LGBT) associations was implemented. During 2017, 10 cases of MenC occurred, compared with 32 and 30 cases reported in 2015 and 2016 respectively, suggesting the effectiveness of the reactive and targeted immunisation programmes.

A new multiplex real-time TaqMan® PCR for quantification of Mycoplasma hyopneumoniae, M. hyorhinis and M. flocculare: exploratory epidemiological investigations to research mycoplasmal association in enzootic pneumonia-like lesions in slaughtered pigs.

A new multiplex qPCR, targeting Mycoplasma (M.) hyopneumoniae, M. hyorhinis and M. flocculare, was developed and the relationship between detection of those mycoplasma species and the extent of gross pneumonia-like lesions in slaughtered pigs lungs were investigated. The multiplex qPCR method targets the p102, p37 and fruA genes and has detection limits of 14, 146 and 16 genome equivalents μl-1 for M. hyopneumoniae, M. hyorhinis and M. flocculare, respectively. In all, 671 lungs were collected and analysed, among them 666 were scored for macroscopic pneumonia and categorized according to the extent of the lesions (no or minor lesions, moderate lesions and extensive lesions). According to results of multiplex qPCR, 59·5% were positive for M. hyopneumoniae, 3·4% for M. hyorhinis and 34·7% for M. flocculare, with on average, 3·1×107 , 9·7×106 and 5·7×106 genome equivalents of mycoplasma ml-1 , respectively. More results showed that no or minor lesions were associated with multiplex qPCR-negative results or qPCR-positive results for M. flocculare. Moderate to extensive lesions were positively correlated with qPCR-positive results for M. hyopneumoniae. Extensive lesions were associated with qPCR-positive results for at least two mycoplasma species (M. hyopneumoniae and M. hyorhinis). The findings also indicated that M. hyopneumoniae and M. hyorhinis significantly increased the odds for a lung to have macroscopic pneumonia. No relationship was found between the extent of lesions and the mycoplasma genome load. This new multiplex qPCR appears to be specific, sufficiently sensitive and repeatable. The validation of this method with field samples guarantees its use for field epidemiological investigations, particularly to gain more insight into the aetiology of the porcine respiratory disease complex.

Suspected Chikungunya Outbreak Investigation, District Gwadar Baluchistan Pakistan March 2017

Background: District Health Officer Gwadar reported chikungunya cases to Provincial Disease Surveillance and Response Unit Quetta and requested for an epidemiological field investigation. Objective: A team sent to confirm, investigate and suggest control measures on 17th March 2017. Methods: A case was defined as a resident of District Gwadar with history of fever with joints pain within last 03 months (January - March 2017). Active case finding was done from 18th to 24th March 2017. Public and private health facilities were visited to review their records. water storage and sanitation practices for vector identification were assessed. Results: 684 patients were identified (over all attack rate = 0.25%). 29 blood samples collected and sent to NIH Islamabad, 72% (n=21) were Chikungunya positive. Among patients 50% (n=344) were male and 50% (n=340) females. Mean age was 27 years (range=1-70 years). Most affected age group was 15 to 19 years (14.6%, n=100), 20 to 24 years (13%,n=92), 25 to 29 years (11%, n=76) and 35 to 39 years (9% n=59) with attack rates 0.35%, 0.38%, 0.38%,and 0.45% respectively.56%(n=382) patients were from Gwadar, 23%(n=161) from Jewani and 21% (n=141) from Pasni with attack rates 0.37%, 0.41% and 0.14% respectively. Investigation revealed that first case was reported on 4th Jan-2017. Being an emerging disease there is lack of knowledge about this disease, its prevention and control among health care providers and community. Sanitation/water storage practices were very poor, larvae of vector also isolated during house hold survey. Conclusions: Lack of proper sanitation and storage techniques in combination of warmer temperature of this coastal district are most probable causes of outbreak. Awareness sessions among community, district administration and healthcare providers regarding chikungunya, its prevention and control were conducted along with vector control on immediate basis through fogging of reservoirs and internal residual spray (IRS). Surveillance system established for regular reporting.

Environmental factors contributing to avian influenza risk in Poyang Lake region, China

The avian influenza (AI) virus isolated from and adapted to an avian host could cause high morbidity, mortality and enormous economic losses in poultry farming. Epidemiological field investigation was performed to study environmental conditions for infected poultry, which possibly spread avian influenza viruses in the Poyang Lake region. A total of 1695 cloacal and oropharyngeal samples were collected in 54 sites in September and December of 2009. Among which, 16 sites with positive samples were confirmed by viral typing and sequencing. The results showed that the highest viral isolation rate was found in live poultry markets. Subsequently, a cross-sectional study was performed to identify environmental risk factors contributing to infection using logistic regression analysis. Based on the predictive model, a risk map was developed to improve our understanding on risk distribution and likelihood of local circulation of avian influenza viruses. In conclusion, (1) the local live poultry market serves as major source of risk for avian influenza; (2) the closer to the administrative centers of counties and the Poyang Lake, the higher is the probability of infection in birds; (3) the human settlements in western, southwestern and southeastern parts of the Poyang Lake were exposed to high risks. Based on the risk factors, combined measures should be taken to control and prevent the avian influenza transmission.