Nonspecific Viral Syndrome Research Articles

Viral Zoonoses

Human infection by zoonotic viruses—pathogens that normally infect animals—may result in no obvious illness, a nonspecific viral syndrome, or more severe illness typically characterized by hemorrhagic fever, encephalitis, or rash arthralgia. Transmission usually occurs by direct contact with or a bite from an infected animal or arthropod. Viral families discussed include Flaviviridae, Bunyaviridae, Arenaviridae, Filoviridae, Togaviridae, Rhabdoviridae, Paramyxoviridae, and Reoviridae, with consideration given to the epidemiology, diagnosis, treatment, and prevention of specific viruses. Hemorrhagic fevers addressed include dengue fever, dengue hemorrhagic fever, yellow fever, Crimean-Congo hemorrhagic fever, and Rift Valley fever; hantavirus infections; and the Marburg and Ebola viruses. Encephalitic fever–causing viruses discussed include La Crosse; Japanese; Murray Valley; St. Louis; tick-borne; West Nile; Powassan; eastern, western, and Venezuelan equine; rabies; Nipah; Barmah Forest; and Colorado tick fever. Rash arthralgia may be caused by the Barmah Forest, Chikungunya, Mayaro, O’nyong-nyong, Ross River, and dengue viruses. Other viral zoonoses considered include monkey B virus, ruminant and primate poxvirus, Newcastle, and foot-and-mouth diseases, as well as vesicular stomatitis virus infection. A diagram depicts the generalized arbovirus maintenance cycle. Tables list the important viral zoonoses that cause human disease, the principal hantaviruses that cause human disease, the arenaviruses that cause significant human illness, and the viral zoonoses endemic in the United States. This review contains 1 figure, 32 tables, and 80 references. Key words: dengue, diagnosis, encephalitis, epidemic, epidemiology, infection, rabies, virus, vaccine

Viral Zoonoses

Human infection by zoonotic viruses—pathogens that normally infect animals—may result in no obvious illness, a nonspecific viral syndrome, or more severe illness typically characterized by hemorrhagic fever, encephalitis, or rash arthralgia. Transmission usually occurs by direct contact with or a bite from an infected animal or arthropod. Viral families discussed include Flaviviridae, Bunyaviridae, Arenaviridae, Filoviridae, Togaviridae, Rhabdoviridae, Paramyxoviridae, and Reoviridae, with consideration given to the epidemiology, diagnosis, treatment, and prevention of specific viruses. Hemorrhagic fevers addressed include dengue fever, dengue hemorrhagic fever, yellow fever, Crimean-Congo hemorrhagic fever, and Rift Valley fever; hantavirus infections; and the Marburg and Ebola viruses. Encephalitic fever–causing viruses discussed include La Crosse; Japanese; Murray Valley; St. Louis; tick-borne; West Nile; Powassan; eastern, western, and Venezuelan equine; rabies; Nipah; Barmah Forest; and Colorado tick fever. Rash arthralgia may be caused by the Barmah Forest, Chikungunya, Mayaro, O’nyong-nyong, Ross River, and dengue viruses. Other viral zoonoses considered include monkey B virus, ruminant and primate poxvirus, Newcastle, and foot-and-mouth diseases, as well as vesicular stomatitis virus infection. A diagram depicts the generalized arbovirus maintenance cycle. Tables list the important viral zoonoses that cause human disease, the principal hantaviruses that cause human disease, the arenaviruses that cause significant human illness, and the viral zoonoses endemic in the United States. This review contains 1 figure, 32 tables, and 80 references. Key words: dengue, diagnosis, encephalitis, epidemic, epidemiology, infection, rabies, virus, vaccine

Clinico-epidemiological study of dengue fever in Ajmer region

Background: Dengue infection is a major challenge to public health, especially in South-East Asia. It present with a diverse clinical spectrum. Estimates suggest that annually over 50 million cases of dengue hemorrhagic fever (DHF) occur in Asian countries with a case fatality rate of less than 5%. Of those with DHF, at least 90% are children younger than 15 years old. In humans, dengue infection causes a spectrum of illness ranging from relatively mild, non-specific viral syndrome known as Dengue fever (DF) to severe hemorrhagic disease and death. Definitive early Dengue diagnosis requires laboratory tests and those suitable for use at this stage of illness are either costly, such as RT-PCR for Dengue; not sufficiently rapid, such as virus isolation. Currently test available are NS1 antigen detection and ELISA for dengue, IgM and IgG antibodies. Objective of this study is to study clinico-epidemiological and haematological features of Dengue infection.Methods: Prospective observational study involving initial 100 registered cases who were serologically confirmed dengue infection for a period of one year.Results: DF, DHF and DSS were found in 41%, 53% and 6% patients respectively. Most common presenting complaint and bleeding manifestation were fever and petechiae. Uncommonly altered sensorium and icterus were found in severe dengue infection. 6% patients had coagulopathy, 37 patients had hepatic involvement and 2 patients had deranged renal function who had DSS. Fever was present in (100%) cases of DF, DHF and DSS. 26% patients had their platelet count <50000/mm3.Conclusions: Dengue is a common disease in the India with wide spectrum of clinical presentations, affecting 5-15 years age group children commonly. It is one of the dreaded fevers but early diagnosis and management according to recent WHO guidelines can decrease case fatality rate significantly.

Illness in Canadian travellers and migrants from Brazil: CanTravNet surveillance data, 2013-2016.

In light of the 2016 summer Olympic games it is anticipated that Canadian practitioners will require information about common illnesses that may affect travellers returning from Brazil. To identify the demographic and travel correlates of illness among recent Canadian travellers and migrants from Brazil attending a network of travel health clinics across Canada. Data was analyzed on returned Canadian travellers and migrants presenting to a CanTravNet site for care of an illness between June 2013 and June 2016. During the study period, 7,707 ill travellers and migrants presented to a CanTravNet site and 89 (0.01%) acquired their illness in Brazil. Tourists were most well represented (n=45, 50.6%), followed by those travelling to "visit friends and relatives" (n=14, 15.7%). The median age was 37 years (range <1-78 years), 49 travellers were men (55.1%) and 40 were women (44.9%). Of the 40 women, 26 (65%) were of childbearing age. Nine percent (n=8) of travellers were diagnosed with arboviruses including dengue (n=6), chikungunya (n=1) and Zika virus (n=1), while another 14.6% (n=13) presented for care of non-specific viral syndrome (n=7), non-specific febrile illness (n=1), peripheral neuropathy (n=1) and non-specific rash (n=4), which are four syndromes that may be indicative of Zika virus infection. Ill returned travellers to Brazil were more likely to present for care of arboviral or Zika-like illness than other ill returned travellers to South America (23.6 per 100 travellers versus 10.5 per 100 travellers, respectively [p=0.0024]). An epidemiologic approach to illness among returned Canadian travellers to Brazil can inform Canadian practitioners encountering both prospective and returned travellers to the Olympic games. Analysis showed that vector-borne illnesses such as dengue are common and even in this small group of travellers, both chikungunya and Zika virus were represented. It is extremely important to educate travellers about mosquito-avoidance measures in advance of travel to Brazil.

Bilateral periorbital ecchymosis in a case with dengue fever

Dear Editor, Dengue is caused by one of four closely related, but antigenically distinct, virus serotypes of the genus Flavivirus and spreads by Aedes aegypti, a domestic, day-biting mosquito that prefers to feed on humans.[1] Infections produce a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease resulting from increased vascular permeability and decreased platelet count.[1] Varying ocular findings in dengue, though rare are known,[24] petechial hemorrhages in conjunctiva being the commonest.[2] Maculopathy is another common manifestation.[5] We hereby, report a case of bilateral periorbital ecchymosis in a case of dengue hemorrhagic fever. A 22-year-old male patient admitted with the diagnosis of dengue hemorrhagic fever was referred from the medicine department of our hospital with complaints of bilateral periorbital swelling and bruising of one-day duration. There was no history of any blunt trauma to the orbit or the head. On examination, both the eyes had periorbital ecchymosis significantly worse in the right eye [Fig. 1]. Both the ocular globes were normal with no restriction of motility and a visual acuity of 20/20 in both eyes. Pupils were reactive to light in both eyes with no relative afferent pupillary defect. Intraocular pressure was 18 mm Hg in both eyes as measured by applanation tonometry. A dilated fundus examination revealed normal fundus with no evidence of hemorrhages or exudates. There was no evidence of ecchymosis elsewhere in the body. Complete blood counts of patient showed a significantly reduced platelet count of 16000/μL (normal range 150000 – 400000/μL). The diagnosis of dengue fever was confirmed by the detection of dengue IgM antibodies.Figure 1: Bilateral periorbital ecchymosis in a patient with dengue feverThe patient received six units of platelet concentrate and supportive therapy was given in the form of antipyretics and volume replacement. No specific treatment was added from the ophthalmic point of view. He was followed up after one week, and there was no change in the periorbital ecchymosis. Platelet count was 28000/μL at this point. Subsequently the patient was lost to follow-up. Dengue fever is considered to be rarely associated with ocular manifestations. The onset of symptoms appears to coincide with the resolution of fever and the nadir of thrombocytopenia.[6] Reported ocular manifestations of dengue fever include subconjunctival hemorrhage, vitreous hemorrhage, choroidal effusions, relative central scotoma, intraretinal hemorrhages, Roth spots, cotton-wool spots, retinal edema, blurring of the optic disk and maculopathy. Platelet count less than 50000/μL predisposes to ocular hemorrhages.[2] Nevertheless, periorbital ecchymosis has not been described as part of the clinical spectrum of dengue fever or any other viral fever. As it occurred with a significantly low platelet count, it appears to be related to thrombocytopenia. Patients with dengue fever who report visual symptoms should be evaluated promptly. Although there is no specific therapy, retinal hemorrhage may be an indication for early and aggressive correction of thrombocytopenia. Ocular alterations in dengue are usually self-limiting. Most of the findings resolve without specific treatment, but occasionally visual recovery may be prolonged or vision may remain permanently impaired in patients with a severe maculopathy.[4] To the best of our knowledge this is the first reported case of bilateral periorbital ecchymosis in a case of dengue hemorrhagic fever.

Dengue Virus, Nepal

To the Editor: Dengue virus belongs to the genus Flavivirus, family Flaviviridae. It has 4 serotypes: dengue virus type 1 (DENV-1), dengue virus type 2 (DENV-2), dengue virus type 3 (DENV-3), and dengue virus type 4 (DENV-4). Dengue virus is maintained in a cycle between humans and Aedes aegypti, domestic day-biting mosquitoes. Dengue virus induces clinical illness, which ranges from a nonspecific viral syndrome (dengue fever [DF]) to severe and fatal hemorrhagic disease (dengue hemorrhagic fever [DHF]). DF/DHF occurs primarily in tropical and subtropical areas of the world. Domestic dengue virus infection occurs in >100 countries; >2.5 billion persons live in these areas. Approximately 100 million cases of DF, 500,000 cases of DHF, and several thousand deaths occur annually worldwide (1). During the past decades, dengue virus has emerged in southern Asia; DF/DHF epidemics have occurred in Bhutan, India, Maldives, Bangladesh, and Pakistan (2–4). From August through November 2006, the number of febrile patients increased in 4 major hospitals in the Terai region of Nepal: Nepalgunj Medical College, Bheri Zonal Hospital in Nepalgunj, Tribhuban Hospital in Dang, and Narayani subregional hospital in Birgunj. Patients with severe symptoms were referred to Sukraraj Tropical and Infectious Disease Hospital, Kathmandu, for diagnosis and treatment. The clinical features in most patients were consistent with signs of DF, but some patients showed signs (high fever, rash, ecchymosis, epistaxis, positive tourniquet test, liver dysfunction, and thrombocytopenia [platelet count <100,000/mm3]) consistent with the World Health Organization (WHO) definition of DHF. Ascites and plural effusion developed in 2 patients. Blood specimens were collected from all patients at the time of admission to the local hospitals. Particle agglutination (PA) assay (Pentax Ltd, Tokyo, Japan) (5) and immunoglobulin (Ig) M–capture ELISA (Dengue/JE IgM Combo ELISA kit, Panbio Ltd, Brisbane, Queensland, Australia) were performed. Dengue virus–specific IgM was detected in 11 patients who had fever, headache, and rash (Table). Each of these patients had negative results for Japanese encephalitis virus–specific IgM. Of the 11 patients, 10 had no history of travel to India or other dengue-endemic countries. DF or DHF was initially diagnosed for 7 patients, and viral encephalitis, typhoid fever, or viral fever was diagnosed for others without serologic tests. Reverse transcription–PCR and virus isolation were performed at Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan, but the dengue virus genome was not detected, and no virus was isolated, likely because sample collection was delayed and the sample was transported to Japan in a deteriorated condition. Table. Clinical and laboratory data for 11 patients admitted to hospitals and diagnosed with dengue fever or dengue hemorrhagic fever, Nepal, 2006* DF/DHF have been considered to be a possible public health threat to Nepal because DF/DHF epidemics have occurred recently in India and Pakistan, which reported several thousand cases and >100 deaths (6). The first DF case in Nepal was reported in 2004 (7). Further, the first DENV-2 strain of Nepal origin was isolated from a Japanese traveler who visited Nepal and in which DF developed after the patient returned to Japan. The isolated DENV-2 (GenBank accession no. {type:entrez-nucleotide,attrs:{text:AB194882,term_id:55771291}}AB194882) was 98% homologous with DENV-2 isolated in India (8). The prevalence of dengue virus antibody was reported to be 10.4% in the southwestern region of Nepal (9). These reports suggest that dengue virus has been circulating in Nepal for several years. Thus, DF/DHF has likely been misdiagnosed and illness caused by dengue virus underestimated in Nepal. In contrast, Japanese encephalitis has been a public health problem in southwestern region of Nepal, and large epidemics have occurred almost every year since 1978 (10). Nepal has no dengue surveillance programs, and health professionals do not usually consider dengue as a differential diagnosis. The emergence occurred in the lowland Terai belt region, which borders the state of Bihar, India. The Aedes mosquito is known to persist in this region. The emerging DENV-2 is likely to have been introduced into Nepal from India.

Lymphoproliferation in children after liver transplantation.

Lymphoproliferation in children after liver transplantation.

Dengue/dengue hemorrhagic fever: the emergence of a global health problem.

Dengue and dengue hemorrhagic fever (DHF) are caused by one of four closely related but antigenically distinct virus serotypes (DEN-1 DEN-2 DEN- 3 and DEN-4) of the genus Flavivirus. Infection with one of these serotypes does not provide cross-protective immunity so persons living in a dengueendemic area can have four dengue infections during their lifetimes. Dengue is primarily an urban disease of the tropics and the viruses that cause it are maintained in a cycle that involves humans and Aedes aegypti a domestic day-biting mosquito that prefers to feed on humans. Infection with a dengue virus serotype can produce a spectrum of clinical illness ranging from a nonspecific viral syndrome to severe and fatal hemorrhagic disease. Important risk factors for DHF include the strain and serotype of the virus involved as well as the age immune status and genetic predisposition of the patient. The first reported epidemics of dengue fever occurred in 1779-1780 in Asia Africa and North America; the near simultaneous occurrence of outbreaks on three continents indicates that these viruses and their mosquito vector have had a worldwide distribution in the tropics for more than 200 years. During most of this time dengue fever was considered a benign nonfatal disease of visitors to the tropics. Generally there were long intervals (10-40 years) between major epidemics mainly because the viruses and their mosquito vector could only be transported between population centers by sailing vessels. (excerpt)