West nile virus infections are here! are we prepared to face another flavivirus epidemic?

Abstract Emerging arthropod-borne viruses (arboviruses), such as chikungunya and Zika viruses, are a major threat to public health in countries like Brazil where biodiversity is high and medical care is sometimes precarious. West Nile fever is a disease caused by the West Nile Virus (WNV), an RNA virus belonging to the Flaviviridae family. It is transmitted by infected mosquitoes to numerous animals like birds, reptiles and mammals, including human and non-human primates. In the last decade, the number of reported cases of WNV infection in humans and animals has increased in the Americas. Circulation of WNV in forests and rural areas in Brazil has been detected based on serological surveys and, in 2014, the first case of West Nile fever was confirmed in a patient from Piauí State. In 2018, the virus was isolated for the first time from a horse from a rural area in the state of Espírito Santo presenting with a neurological disorder; this raises the possibility that other cases of WNV encephalitis may have occurred without clinical recognition and without laboratory diagnosis by specific assays. The imminent WNV outbreak poses a challenge for Brazilian clinicians and researchers. In this review, we summarize the basic biological and ecological characteristics of this virus and the clinical presentation and treatment of febrile illnesses caused by WNV. We also discuss the epidemiological aspects, prophylaxis of WNV infections, and monitoring strategies that could be applied in the possibility of a WNV outbreak in Brazil.

Arboviruses emerging in Brazil: challenges for clinic and implications for public health / Arboviroses emergentes no Brasil: desafios para a clínica e implicações para a saúde pública

ABSTRACT Arboviruses have been emerging in different parts of the world due to genetic changes in the virus, alteration of the host and vector population dynamics, or because of anthropogenic environmental factors. These viruses’ capacity for adaptation is notable, as well as the likelihood of their emergence and establishment in new geographic areas. In Brazilian epidemiologic scenario, the most common arboviruses are DENV, CHIKV, and ZIKV, although others may spread in the country. Little is yet known of the impact of viral co-circulation, which would theoretically result in more intense viremia or other immunological alterations that could trigger autoimmune diseases, such as Guillain-Barré syndrome. The impact on morbidity and mortality intensifies as extensive epidemics lead to a high number of affected individuals, severe cases, and implications for health services, mainly due to the absence of treatment, vaccines, and effective prevention and control measures.

RESUMO Notifica-se a emergência de arboviroses em diferentes regiões do planeta em decorrência de mudanças genéticas no vírus, alteração da dinâmica populacional de hospedeiros e vetores ou por fatores ambientais de origem antropogênica. É notável a capacidade de adaptação desses vírus e a possibilidade de emergirem e se estabelecerem em novas áreas geográficas. No contexto epidemiológico brasileiro, os arbovírus de maior circulação são DENV, CHIKV e ZIKV, embora existam outros com potencial de disseminação no País. O impacto da cocirculação viral ainda é pouco conhecido, a qual teoricamente resultaria em viremias mais intensas ou outras alterações imunológicas que poderiam ser o gatilho para doenças autoimunes, como a síndrome de Guillain-Barré. O impacto na morbidade e mortalidade se intensifica à medida que extensas epidemias pressupõem grande número de indivíduos acometidos, casos graves e implicações sobre os serviços de saúde, principalmente diante da ausência de tratamento, vacinas e medidas efetivas de prevenção e controle.

Enfermedades infecciosas emergentes y reemergentes: información actualizada / Emerging and re-emerging infectious diseases: updated information

A fines del siglo XX, una gran diversidad de factores contribuyeron a la aparición de enfermedades infecciosas emergentes, con importante impacto en la salud pública. Estas enfermedades, en general, se caracterizan por ser de reciente aparición, provocar una inusual incidencia en una población o área geográfica, o reaparecer luego de haber cesado su actividad por largo tiempo(1). Algunas enfermedades emergentes, como VIH/SIDA, persisten por años, en tanto que otras, luego de su aparición, duran períodos limitados. Múltiples factores, además del agente infeccioso, intervienen en el complejo proceso que determina la emergencia de enfermedades infecciosas. Constantemente, miles de microorganismos potencialmente patógenos se diseminan en nuevas áreas geográficas, pero solo unos pocos llegan a sobrevivir y causar enfermedades, favorecidos por condicionantes socioeconómicas, ambientales y ecológicas. Este fenómeno mundial requiere una vigilancia epidemiológica constante, con una infraestructura nacional y regional que asegure una alerta temprana frente a la emergencia o reemergencia de esas enfermedades.

In the late 20th century, several different factors contributed to the appearance of emerging infectious diseases that had a great impact on public health. In general, these diseases are characterized by appearing for the first time, they rapidly increase in incidence in certain populations or geographical area, or they have been known for some time although they have disappeared for a long time. A few infectious diseases like HIV/AIDS have persisted for several years, while others, after appearing, last limited periods of time. Multiple factors, apart from the infectious agent, take part in the complex process that results in the emergence of an infectious disease. Thousands of potentially pathogenic microorganisms are constantly disseminated in new geographical areas, although just a few manage to survive and cause diseases, favored by social, economic, environment and ecologic factors. This global phenomenon requires continuous epidemiological surveillance, with a national and regional infrastructure that enables an early alert upon these diseases that emerge or re-emerge.

No final do século XX, muitos fatores diferentes contribuíram para o surgimento de doenças infecciosas emergentes, com importante impacto sobre a saúde pública. De maneira geral, estas doenças se caracterizam por haver surgido recentemente, provocar uma incidência pouco comum em uma população ou área geográfica, ou reaparecer depois de haver cessado sua atividade por um tempo prolongado (1). Algumas doenças emergentes, como VIH/SIDA, persistem por anos, enquanto outras têm uma duração limitada. Além do agente infeccioso, muitos outros fatores intervêm no complexo processo que determina o surgimento de doenças infecciosas. Constantemente, milhares de micro-organismos potencialmente patógenos se disseminam em novas áreas geográficas, mas somente poucos são capazes de sobreviver e causar doenças, favorecidos por condicionantes socioeconômicos, ambientais e ecológicos. Este fenômeno mundial requer uma vigilância epidemiológica constante, com una infraestrutura nacional e regional que garanta um alerta precoce frente à emergência ou reemergência de essas doenças.

Reemergence of yellow fever: detection of transmission in the State of São Paulo, Brazil, 2008 / Reemergência de febre amarela: detecção de transmissão no Estado de São Paulo, Brasil, 2008

INTRODUCTION: Following yellow fever virus (YFV) isolation in monkeys from the São José do Rio Preto region and two fatal human autochthonous cases from the Ribeirão Preto region, State of São Paulo, Brazil, two expeditions for entomological research and eco-epidemiological evaluation were conducted. METHODS: A total of 577 samples from humans, 108 from monkeys and 3,049 mosquitoes were analyzed by one or more methods: virus isolation, ELISA-IgM, RT-PCR, histopathology and immunohistochemical. RESULTS: Of the 577 human samples, 531 were tested by ELISA-IgM, with 3 positives, and 235 were inoculated into mice and 199 in cell culture, resulting in one virus isolation. One sample was positive by histopathology and immunohistochemical. Using RT-PCR, 25 samples were processed with 4 positive reactions. A total of 108 specimens of monkeys were examined, 108 were inoculated into mice and 45 in cell culture. Four virus strains were isolated from Alouattacaraya. A total of 931 mosquitoes were captured in Sao Jose do Rio Preto and 2,118 in Ribeirão Preto and separated into batches. A single isolation of YFV was derived from a batch of 9 mosquitoes Psorophoraferox, collected in Urupês, Ribeirão Preto region. A serological survey was conducted with 128 samples from the municipalities of São Carlos, Rincão and Ribeirão Preto and 10 samples from contacts of patients from Ribeirão Preto. All samples were negative by ELISA-IgM for YFV. CONCLUSIONS: The results confirm the circulation of yellow fever, even though sporadic, in the Sao Paulo State and reinforce the importance of vaccination against yellow fever in areas considered at risk.

INTRODUÇÃO: A partir do isolamento do vírus febre amarela (VFA), de macacos, da região de São José do Rio Preto e de dois casos humanos autóctones fatais, da região de Ribeirão Preto, Estado de São Paulo, foram realizadas duas expedições para pesquisa entomológica e avaliação ecoepidemiológica. MÉTODOS: Um total de 577 amostras de humanos, 108 de macacos e 3.049 mosquitos foram analisados por um ou mais métodos: isolamento viral, ELISA-IgM, RT-PCR, histopatologia e imunohistoquímica. RESULTADOS: De 577 amostras humanas, 531 foram testadas por ELISA-IgM, sendo 3 positivas, 235 foram inoculadas em camundongos, 199 em cultura de células, obtendo-se 1 isolamento viral. Uma amostra foi positiva por histopatologia e imunohistoquímica. Por RT-PCR foram processadas 25 amostras com 4 reações positivas. Os 108 espécimes de macacos foram inoculados em camundongos, 45 em cultura de células, obtendo-se 4 isolamentos de VFA, de Alouatta caraya. Um total de 931 mosquitos foram capturados em São José do Rio Preto e 2.118 em Ribeirão Preto e separados em lotes. Um único isolamento de VFA foi derivado de um lote de 9 mosquitos Psorophora ferox, coletados em Urupês, região de Ribeirão Preto. Um inquérito sorológico foi realizado com 128 amostras dos municípios de São Carlos, Rincão e Ribeirão Preto e mais 10 amostras de contactantes de pacientes de Ribeirão Preto. Todas as amostras foram negativas por ELISA-IgM para VFA. CONCLUSÕES: Os resultados confirmam a circulação, mesmo que esporádica, do VFA no Estado de São Paulo e reforça a importância da vacinação antiamarílica nas áreas consideradas de risco.

The emerging of the fifth malaria parasite (Plasmodium knowlesi): a public health concern?

After examining the most recent scientific evidences, which assessed the role of some malaria plasmodia that have monkeys as natural reservoirs, the authors focus their attention on Plasmodium knowlesi. The infective foci attributable to this last Plasmodium species have been identified during the last decade in Malaysia, in particular in the states of Sarawak and Sabah (Malaysian Borneo), and in the Pahang region (peninsular Malaysia). The significant relevance of molecular biology assays (polymerase chain reaction, or PCR, performed with specific primers for P. knowlesi), is underlined, since the traditional microscopic examination does not offer distinguishing features, especially when the differential diagnosis with Plasmodium malariae is of concern. Furthermore, Plasmodium knowlesi disease may be responsible of fatal cases, since its clinical presentation and course is more severe compared with those caused by P. malariae, paralleling a more elevated parasitemia. The most effective mosquito vector is represented by Anopheles latens; this mosquito is a parasite of both humans and monkeys. Among primates, the natural hosts are Macaca fascicularis, M. nemestina, M. inus, and Saimiri scirea. When remarking the possible severe evolution of P. knowlesi malaria, we underline the importance of an early recognition and a timely management, especially in patients who have their first onset in Western Hospitals, after journeys in Southeast Asian countries, and eventually participated in trekking excursions in the tropical forest. When malaria-like signs and symptoms are present, a timely diagnosis and treatment become crucial. In the light of its emerging epidemiological features, P. knowlesi may be added to the reknown human malaria parasites, whith includes P. vivax, P. ovale, P. malariae, and P. falciparum, as the fifth potential ethiologic agent of human malaria. Over the next few years, it will be mandatory to support an adequate surveillance and epidemiological network. In parallel with epidemiological and health care policy studies, also an accurate appraisal of the clinical features of P. knowlesi-affected patients will be strongly needed, since some preliminary experiences seem to show an increased disease severity, associated with increased parasitemia, in parallel with the progressive increase of inter-human infectious passages of this emerging Plasmodium.

Zoonosis con reservorios silvestres: Amenazas a la salud pública y a la economía: [revisión] / Zoonoses with wildlife reservoirs: A threat to public health and the economy: [review]

The world is experiencing an increase in emergent infections as a result of anthropogenic changes of the biosphere and globalization. Global warming unrestricted exploitation of natural resources such as forests and fisheries, urbanization, human migration, and industrialization of animal husbandry cause environmental destruction and fragmentation. These changes of the biosphere favor local emergence of zoonoses from their natural biotopes and their interaction with domestic animals and human populations. Subsequently, international commerce, human and animal migration and travel, favor the dissemination of these zoonotic pathogens worldwide. Chile is undergoing an important degradation of many wild-life biotopes, affecting their diversity and contributing to the dissemination of zoonoses such as Chagas disease, Hantavirus, rabies, fish tapeworms, and marine vibriosis. Moreover, agents of many other zoonoses such as ¡eptospirosis, hydatidosis, salmonellosis, rabies, brucellosis and anthrax have been detected in different wild-life environments in the country. The intensification and accelerations of the anthropogenic deterioration of the biosphere in Chile, as results of the unrestricted utilization of natural resources and global climate change, suggests that emergence of new zoonoses in the near future will lead to important public health and economic problems. Forestalling of these problems will require active epidemiológica! surveillance of wild and domestic animals with a wide range of modern molecular and ancillary epidemiológica! tools. This also demands government and private sector (i.e., animal husbandry) intervention, funding and the collaboration of professionals in human and veterinary medicine with those in the environmental sciences including ecology, climatology and oceanography.

Emergent arboviruses in Brazil

Brazil is a large tropical country (8,514,215km²) with 185,360,000 inhabitants. More than one third of its territory is covered by tropical forests or other natural ecosystems. These provide ideal conditions for the existence of many arboviruses, which are maintained in a large variety of zoonotic cycles. The risk that new arboviruses might emerge in Brazil is related to the existence of large, densely populated cities that are infested by mosquitoes such as Culex and the highly anthropophilic Aedes aegypti. Infected humans or animals may come into these cities from ecological-epidemiological settings where arbovirus zoonoses occur. This study analyzes the risk of emergence of the alphaviruses Mayaro, Venezuelan equine encephalitis, Eastern equine encephalitis and Chikungunya; the flaviviruses yellow fever, Rocio, Saint Louis encephalitis and West Nile; and the orthobunyavirus Oropouche.

O Brasil é país tropical de grande extensão territorial (8.514.215km²) e com 185.360.000 habitantes. Mais de 1/3 deste território é recoberto por florestas tropicais ou outros ecossistemas naturais com condições ideais para a ocorrência de diversas arboviroses as quais são mantidas em uma grande variedade de ciclos zoonóticos. O risco para a emergência de novos arbovirus no Brasil relaciona-se à existência de cidades grandes, populosas e infestadas por mosquitos Culex bem como o altamente antropofílico Aedes aegypti. Nas cidades poderiam ser introduzidos seres humanos ou animais infectados oriundos de sítios eco-epidemiológicos onde existem zoonoses arbovíricas. Neste trabalho, analisa-se o risco de emergência dos alphavirus Mayaro, da encefalite eqüina venezuelana, da encefalite eqüina do leste e Chikungunya, dos flavivirus, da febre amarela, Rocio, da encefalite de Saint Louis e do Nilo Ocidental, e do orthobunyavirus Oropouche.

Doenças emergentes e reemergentes / Emerging and reemerging infectious diseases

Apesar do grande desenvolvimento cientifico e tecnológico alcançado neste século, o impacto de sua economia e da exploração do planeta de forma irresponsável e inadequada, a busca desenfreada pela eficiência, qualidade, perfeccionismo impõem estresse, isolamento, competição, degradação da natureza, migrações populacionais, valorização do consumo, distúrbios do afeto, descuido com o controle de vetores responsáveis por doenças antes controladas e alterações de ecossistemas, da natureza externa e interna ao homem. Tudo isso resulta em desequilíbrio e desarmonia e provoca o surgimento e ressurgimento de doenças que indicam o equívoco humano na busca de acumulação de bens e da exploração do trabalho como requisitos para a felicidade e bem-estar.

This article discuss de emerging and reeemerging of discases on the twenty century. They also comment some possible factors that may contribute to this epidemiologic alterations.