The Zika outbreak of the 21st century.

The Zika virus outbreak has captivated the attention of the global audience and information has spread rapidly and wildly through the internet and other media channels. This virus was first identified in 1947, when it was isolated from a sentinel rhesus monkey placed by British scientists working at the Yellow Fever Research Laboratory located in the Zika forest area of Uganda, hence its name, and is transmitted primarily by the mosquito vector, Aedes aegypti. The fact that the rhesus macaque is an Asian species being placed in an African forest brings to mind the possibility of rapid adaptation of the virus from an African to Asian species, an issue that has not been considered. Whether such adaptation has played any role in acquiring pathogenicity due to cross species transmission remains to be identified. The first human infection was described in Nigeria in 1954, with only scattered reports of about a dozen human infections identified over a 50-year period. It was not until 2007 that Zika virus raised its ugly head with infections noted in three-quarters of the population on the tiny island of Yap located between the Philippines and Papua New Guinea in the western Pacific Ocean, followed by a major outbreak in French Polynesia in 2013. The virus remained confined to a narrow equatorial band in Africa and Asia until 2014 when it began to spread eastward, first toward Oceania and then to South America. Since then, millions of infected individuals have been identified in Brazil, Colombia, Venezuela, including 25 additional countries in the Americas. While the symptoms associated with Zika virus infection are generally mild, consisting of fever, maculopapular rash, arthralgia and conjunctivitis, there have been reports of more severe reactions that are associated with neurological complications. In pregnant women, fetal neurological complications include brain damage and microcephaly, while in adults there have been several cases of virus-associated Guillain-Barre syndrome. The virus was until recently believed to only be transmitted via mosquitoes. But when the Zika virus was isolated from the semen specimens from a patient in Texas, this provided the basis for the recent report of possible sexual transmission of the Zika virus. Due to the neurological complications, various vectors for infection as well as the rapid spread throughout the globe, it has prompted the World Health Organization to issue a global health emergency. Various governmental organizations have recommended that pregnant women do not travel to countries where the virus is epidemic, and within the countries affected by the virus, recommendations were provided for women of childbearing age to delay pregnancy. The overall public health impact of these above findings highlights the need for a rapid but specific diagnostic test for blood banks worldwide to identify those infected and for the counseling of women who are pregnant or contemplating pregnancy. As of this date, there are neither commercially licensed diagnostic tests nor a vaccine. Because cross-reactivity of the Zika virus with dengue and Chikungunya virus is common, it may pose difficulty in being able to quickly develop such tests and vaccines. So far the most effective public health measures include controlling the mosquito populations via insecticides and preventing humans from direct exposure to mosquitoes

Hotspots: Exotic mosquito risk profiles for New Zealand

This document reports the main findings of the first systematic, spatial analyses of risks to New Zealand associated with exotic mosquitoes of current public health concern

Personal protective strategies for dengue disease: simulations in two coexisting virus serotypes scenarios

Dengue fever is a common mosquito-borne viral infectious disease in the world and is widely spread, especially in tropical and subtropical regions. At this moment, one of the best ways to fight the disease is to prevent mosquito bites. In this study, we present a mathematical model that carefully considers personal protection for humans. It is an epidemiological model that translates the dengue disease through a system of differential ordinary equations which takes in consideration the dynamics of the disease between human and mosquito populations. This model incorporates a parameter that simulates personal protection measures, namely insect repellent, special clothes, or bed nets, and a parameter that asserts the effectiveness of public awareness to the importance of using personal protective equipment. In 2012 there was a dengue disease outbreak in Madeira Island, in Portugal, and this study not only tries to predict what could happen if a second outbreak occurs, where it is considered that there are two serotypes of Dengue disease, but also tries to predict the effects and the importance of taking personal protection measures. The results show that the level of personal measures and the time that people are compelled to use them have a significant impact to prevent dengue disease.publishe

Wolbachia pipientis: A potential candidate for combating and eradicating dengue epidemics in Pakistan

AbstractDengue virus syndrome is an emerging global health challenge which is endemic in tropical countries like Pakistan. In recent years dengue incidences have increased considerably in different areas of Pakistan with more sever impacts on urban and peri-urban populations. This review is an effort to highlight the changing epidemiology of dengue fever, role of Government of Pakistan in disease management and control using preventive and community based approaches in the region. Moreover, there is an emphasis on application of Wolbachia as novel, inexpensive and environmentally benign candidate for control and eradication of dengue transmitting vectors

Analysis of an age-structured dengue model with multiple strains and cross immunity

Dengue fever is a typical mosquito-borne infectious disease, and four strains of it are currently found. Clinical medical research has shown that the infected person can provide life-long immunity against the strain after recovering from infection with one strain, but only provide partial and temporary immunity against other strains. On the basis of the complexity of transmission and the diversity of pathogens, in this paper, a multi-strain dengue transmission model with latency age and cross immunity age is proposed. We discuss the well-posedness of this model and give the terms of the basic reproduction number R0 = max{R1, R2} , where Ri is the basic reproduction number of strain i (i = 1, 2). Particularly, we obtain that the model always has a unique diseasefree equilibrium P0 which is locally stable for R0 1, the strain-i dominant equilibrium Pi is locally stable for Rj < R∗ i (i, j = 1, 2, i 6= j). Additionally, the threshold criteria on the uniformly persistence, the existence and global asymptotically stability of coexistence equilibrium are also obtained. Finally, these theoretical results and interesting conclusions are illustrated with some numerical simulations

Climatic conditions : conventional and nanotechnology-based methods for the control of mosquito vectors causing human health issues

Climate variability is highly impacting on mosquito-borne diseases causing malaria and dengue fever across the globe. Seasonal variability change in temperature and rainfall patterns are impacting on human health. Mosquitoes cause diseases like dengue fever, yellow fever, malaria, Chikungunya, West Nile and Japanese encephalitis. According to estimations by health organizations, annually one million human deaths are caused by vector-borne diseases, and dengue fever has increased about 30-fold over the past 50 years. Similarly, over 200 million cases of malaria are being reported annually. Mosquito-borne diseases are sensitive to temperature, humidity and seasonal variability. Both conventional (environmental, chemical, mechanical, biological etc.) and nanotechnology-based (Liposomes, nano-suspensions and polymer-based nanoparticles) approaches are used for the eradication of Malaria and dengue fever. Now green approaches are used to eradicate mosquitoes to save human health without harming the environment. In this review, the impact of climatic conditions on mosquito-borne diseases along with conventional and nanotechnology-based approaches used for controlling malaria and dengue fever have been discussed. Important recommendations have been made for people to stay healthy

Epidemiological trends and risk factors associated with dengue disease in Pakistan (1980–2014): a systematic literature search and analysis

BACKGROUND: Dengue is becoming more common in Pakistan with its alarming spreading rate. A historical review needs to be carried out to find the root causes of dengue dynamics, the factors responsible for its spread and lastly to formulate future strategies for its control. METHODS: We searched (January, 2015) all the published literature between 1980 and 2014 to determine spread/burden of dengue disease in Pakistan. RESULTS: A total of 81 reports were identified, showing high numbers of dengue cases in 2010, 2011, and 2013. The tendency of dengue to occur in younger than in older age groups was evident throughout the survey period and all four serotypes were recorded, with DENV1 the least common. Most dengue hemorrhagic fever (DHF) cases fell in the 20-45 years age range. High frequencies tended to be observed first in the Southern coastal region characterized by mild winters and humid warm summers and then the disease progressed towards the lowland areas of the Indus plain with cool winters, hot summers and monsoon rainfall. Based on this survey, new risk maps and infection estimates were identified reflecting public health burden imposed by dengue at the national level. CONCLUSIONS: Our study showed that dengue is common in the three provinces of Pakistan, i.e., Khyber Pakhtunkhwa (KP), Punjab and Sindh. Based on the literature review as well as on our study analysis the current expansion of dengue seems multifactorial and may include climate change, virus evolution, and societal factors such as rapid urbanization, population growth and development, socioeconomic factors, as well as global travel and trade. Due to inadequate remedial strategies, effective vector control measures are essential to target the dengue vector mosquito where high levels of human-vector contact occur. The known social, economic, and disease burden of dengue is alarming globally and it is evident that the wider impact of this disease is grossly underestimated. An international multi-sectoral response, outlined in the WHO Global Strategy for Dengue Prevention and Control, 2012-2020, is now essential to reduce the significant influence of this disease in Dengue endemic areas. Overall gaps were identified in knowledge around seroprevalence, dengue incidence, vector control, genotype evolution and age-stratified serotype circulation

Dengue fever and severe dengue in Barbados, 2008–2016

Analysis of the temporal, seasonal and demographic distribution of dengue virus (DENV) infections in Barbados was conducted using national surveillance data from a total of 3994 confirmed dengue cases. D