Infectious Disease

Legionellosis is a respiratory illness that is mostly (80-90%) caused by the bacterium Legionella pneumophila. It is associated with a mild febrile illness, Pontiac fever, or Legionnaires'™ disease (1), a source of severe, community-acquired pneumonia. Legionella bacteria mostly affect elderly persons specifically those with underlying debilitating illnesses and with lowered immune systems. Water is the major natural reservoir for Legionella, and the pathogen is found in many different natural and artificial aquatic environments such as cooling towers or water systems in buildings, including hospitals. An abrupt increase in the incidence of Legionnaires' has been noted since 2003 throughout the nation. According to CDC, about 6,000 cases of Legionnaires' disease were reported in the United State in 2015 (1). Incidence rates of Legionnaires for the year 2015 were 1.06 and 1.90 (ref) for Texas and the United States respectively (2). Increased number of reported cases might be due to the fact of an older population, more at risk individuals, aging plumbing infrastructure, and increased testing for Legionnaires' disease by various hospitals and laboratories.

Objective: To study trends and patterns in legionnaires' disease cases in Houston, Texas, from 2014-2017.

West Nile virus (WNV) is considered the leading cause of domestically acquired arboviral disease and is spread through mosquitoes. In general, the majority of the cases are asymptomatic. One in five people infected will display mild symptoms like fever, headache, body ache, nausea, and vomiting. Only about 1 in 150 people infected will develop serious neurologic complications such as encephalitis and meningitis. According to CDC, in 2017, there were 133 confirmed cases including 5 deaths and 14 presumptive blood donors reported in the State of Texas. Out of the confirmed cases, there were 85 neuroinvasive and 48 non-neuroinvasive disease cases.

Objective: To demonstrate an overview of the epidemiological and clinical distribution of reportable West Nile cases in Houston, Texas, from 2015-2017.

Intestinal infectious diseases (IID) is a common cause of illness in the community and results in a high burden of consultations to general practice, mostly affecting the health of infants, preschool children, young adults and elderly people, especially those living in low income countries. According to the published study on the global burden of disease, intestinal infectious diseases were responsible for 221,300 deaths worldwide in 2013. The Chinese Ministry of Health has listed bacillary dysentery, amebic dysentery, typhoid fever and paratyphoid fever as notifiable Class-B communicable diseases and other infectious diarrhea as notifiable Class-C communicable diseases to be included in the surveillance system and reporting network since 2004. Many studies of IID in different regions have been published. However, the epidemiological characteristics and space-time patterns of individual-level IID cases in a major city such as Beijing are still unknown. We aim to analyze the epidemiology features and identify space-time clusters of Beijing IID at a fine spatial scale in this study.

Objective: To investigate epidemiological features and identify high relative risk space-time Intestinal infectious diseases clusters at the township level in Beijing city in order to provide the scientific evidence for making prevention and control measures.

Nigeria is the only country in Africa yet to be certified free of Wild Polio Virus (WPV). The country consists of 36 States and a Federal Capital Territory. Gombe is one of the 19 Polio high risk States in the North-eastern geo-political zone of the country. The last case of WPV isolated in Gombe State was in 2013. One of the strategies for Polio eradication is a sensitive Acute Flaccid Paralysis (AFP) surveillance system in which any AFP is promptly detected and timely investigated. The focus of the investigation is to analyze two faecal samples of the patient, and/or sometimes those from contacts for any possible isolation of Polio Virus (PV). AFP surveillance is meant to be applicable to any human population at any time; however, there are situations in which there are good reasons to suspect that negative results of AFP surveillance are not reliable. Supplementary information is required in such situations and one approach for that is Environmental Surveillance (ES), in which a search for PV is made in environmental specimens contaminated by human feaces. ES in the African region started in Nigeria in July 2011. Since the introduction of this strategy, it has achieved its objective of complimenting the AFP surveillance system. There has been a gradual increase in the number of ES sites in Nigeria from 2011 to date. The increase is largely due to the successes recorded in terms of the PV isolation from the sites, PV epidemiology, the large population size and mobility. The last cases of WPV1 and WPV3 from environmental samples had dates of collection in May 2014 (Kaduna) and July 2012 (Kano) respectively. ES was initiated in Gombe State in December 2016. Four ES sites were identified and sample collection began soon after training of personnel responsible for collection of the sewage sample. The four identified ES sites are Baba Roba Valley, Unguwauku Railway Bridge, Gadan Bayan Moonshine and Dan Gusau Bridge. Since inception of ES in Gombe State, ambiguous Vaccine Derived Poliovirus type 2 (aVDPV2) were confirmed from sewage samples collected from Baba Roba Valley site on the 30th January 2017 and from Dan Gusau Bridge site on the 6th March 2017. In 2018, a circulating Vaccine Derived Poliovirus type 2 (cVDPV2) was also detected from sewage samples collected on the 9th April 2018 from Baba Roba Valley site. We reviewed the laboratory results from the 2 surveillance methods so as to evaluate the VDPV2 isolation rate.

Objective: To evaluate Vaccine Derived Polio Virus 2 isolation rate from Environmental Surveillance and its contribution to Polio Eradication Initiative (PEI).

Influenza causes a significant burden to the world every year. In the temperate zone, influenza usually prevalent in the winter season, however, it is hardly predictable when the influenza epidemic will begin and when the peak activity will come. Influenza has a peak in early winter sometimes and a peak in late winter in another year. However, it is not well known what determines these epidemics timing, and the global climate change is expected to influence the timing of influenza epidemics.

Objective: This study aimed to explore the effects of El NiÃno and La Nina events on the timing of influenza A peak activity in European countries.

Evidence about the value of syndromic surveillance data for outbreak detection is limited. In July 2018, a salmonellosis outbreak occurred following a family reunion of 300 persons held in Camden County, Georgia, where one meal was served on 7/27/2018 and on 7/28/2018.

Objective: Describe how the Georgia Department of Public Health (DPH) used data from its State Electronic Notifiable Disease Surveillance System (SendSS) Syndromic Surveillance (SS) module for early detection of an outbreak of salmonellosis in Camden County, Georgia.

An essential tool for infectious disease surveillance is to have a timely and cost-effective testing method. For this purpose, laboratories frequently use specimen pooling to assay high volumes of clinical specimens. The simplest pooling algorithm employs a two-stage process. In the first stage, a set number of specimens are amalgamated to form a group that is tested as if it were one specimen. If this group tests negatively, all individuals within the group are declared disease free. If this group tests positively, a second stage is implemented with retests performed on each individual. This testing algorithm is repeated across all individuals that need to be tested. In comparison to testing each individual specimen, large reductions in the number of tests occur when overall disease prevalence is small because most groups will test negatively. Most pooling algorithms have been developed in the context of single-disease assays. New pooling algorithms are developed in the context of multiplex (multiple-disease) assays applied over two or three hierarchical stages. Individual risk information can be employed by these algorithms to increase testing efficiency.

Objective: To develop specimen pooling algorithms that reduce the number of tests needed to test individuals for infectious diseases with multiplex assays.

Contact tracing is an important strategy employed in surveillance to aid prompt detection of infectious disease and control outbreaks. It involves the identification of those who have come in contact with an infectious person and following them up for the duration of the incubation period of the disease to promptly detect symptoms and signs and institute treatment thus reducing chances of disease spread to other susceptible individuals. It is a primary means of disease prevention. The importance of cooperation from contacts being traced cannot be overemphasized as they are required to promptly report symptoms, avoid gatherings and travelling until they are cleared by the surveillance team. The follow-up should also link contacts who become symptomatic to designated care centers. In 2014, during the Ebola outbreak in Nigeria, the disease spread from Lagos to another State in the country by a contact who travelled out of Lagos to Rivers state. To identify risk factors among contacts of Lassa fever cases which can predispose to disease spread and institute control measures, we interviewed primary contacts of Lassa fever cases during an outbreak response in Kogi State Nigeria, 2016.

Objective: To identify risk factors among contacts of Lassa fever cases which can predispose to disease spread and institute control measures.

Nepal being a developing country has many health problems, which escalate in intensity at different times of the year or in epidemic form. Amebiasis is one of the infectious diseases that is highly seen in rural area of Nepal caused by Entamoeba species. Recent reports show that open defecation, drinking untreated water, unsanitary habits and lack of basic health knowledge cause higher mortality and morbidity in our country. E. histolytica is an anaerobic pathogenic parasitic. However, E. dispar and E.moshkovskii exits as non-pathogenic. Likewise, E. histolytica, E. dispar and E. moshkovskii are morphologically identical but genetically distinct species.

Objective: To find out the prevalence of Entamoeba species in rural community of Nepal. The purpose of the study is to evaluate Nested PCR, microscopic examination and Elisa assay for detection and differentiation of Entamoeba species.

Arboviral infections have become a significant public health problem with the emergence and re-emergence of arboviral diseases worldwide in recent decades. Given the increasing number of cases, geographic spread, but also health, social and economic impact of arboviral outbreaks, estimating their true burden represents a crucial issue but remains a difficult task. In French Guiana, the epidemiology of arboviral diseases has been marked by the occurrence several major dengue fever (DENV) outbreaks over the past few decades, recent emergences of Chikungunya (CHKV) and Zika virus (ZIKV) and the circulation of Mayaro virus (MAYV).

Objective: To assess the level of circulation of DENV, CHIKV, ZIKV, MAYV in French Guiana.