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Kawasaki disease (KD) or mucocutaneous lymph node syndrome is a childhood disorder that was first reported by Tomisaku Kawasaki in 1967.1 The characteristic signs are conjunctival congestion, skin rash, skin desquamation of the peripheral limbs, erythema of the oral cavity, lips, and palms, and cervical lymphadenopathy.1 KD most commonly develops in infants. Approximately 85% of the patients with KD are under 5 years of age.2,3 The occurrence of KD is rare in adolescents and adults.4 The specific cause of KD is still unclear, but some reports suggest that it is triggered by bacterial or viral infections.5–7 Herein, we describe a rare case of adult-onset KD which revealed to be concurrently infected by Coxsackievirus A4.
Here, we describe a case of adult-onset KD which revealed to be concurrently infected by Coxsackievirus A4. Adult-onset KD is rare, and this is a very rare case of KD and concurrent Coxsackievirus A4 infection.
KD most commonly develops in infants. The annual incidence is 67 cases per 100,000 children in Japan and 5.6 cases per 100,000 children in the USA. Children under 5 years of age constitute 88.5% of reported cases.2,3 KD occurs predominantly in children while rarely in adolescents and adults.4 The oldest reported case was that of a 68-year-old Caucasian man from France in 2005.9 The diagnostic criteria for KD as defined by the Centers for Disease Control and Prevention include unexplained fever lasting 5 days or more and at least four out of the five following criteria: 1) polymorphic exanthema; 2) changes in the peripheral extremities, that is, erythema and/or indurative edema of the palms and soles (acute phase) or desquamation around the finger tips (convalescent phase); 3) bilateral non-exudative conjunctival injection; 4) changes in the oropharynx, that is, injected or fissured lips, strawberry tongue, and injected pharynx; and 5) acute nonsuppurative cervical lymphadenopathy (>1.5 cm in diameter). Patients with fewer than four of these clinical signs can be diagnosed as having atypical KD if coronary artery abnormalities are present.8 Additionally, it is necessary to exclude the possibility of other diseases that cause fever and rash (eg, toxic shock syndrome, streptococcal scarlet fever, measles, other viral infections, Stevens–Johnson syndrome, or a drug reaction).
Desquamation is typically found during the convalescent phase. However, in patients who develop KD in adulthood, the time of onset of desquamation is varied. Some of these patients have been reported to develop desquamation during the acute phase of KD with fever.9,10 This may be associated with the fact that multiple factors cause KD and that the mechanism of KD differs between adults and children. In our patient, desquamation appeared relatively early and then improved. Although the side effects of cefcapene-pivoxil and loxoprofen should be considered in the differential diagnosis, both drugs were used without adverse effects in this patient before this episode. Item (2) in the diagnostic criteria was satisfied even if desquamation was excluded. Therefore, desquamation does not affect the diagnosis.
The CDC defines a laboratory-confirmed case of MERS-CoV as a patient with a positive PCR from a respiratory sample, and a probable case as a patient who had close contact with a confirmed case but inconclusive laboratory evidence. The incubation period for the presentation of MERS-CoV symptoms is 2–14 days and it remains unknown whether patients are infectious during the incubation period. The average age of presentation is 50 years, with a male predominance.
Clinically, MERS-CoV causes symptoms of upper and lower RTIs. The severity of symptoms varies widely. Most asymptomatic cases have been discovered through screening after contact with a known case. Presenting signs and symptoms may include high-grade fever, non-productive cough, dyspnea, headache, myalgia, nausea, vomiting, and diarrhea that may precede the respiratory symptoms,. Renal failure has been frequently reported, yet no conclusive evidence of a direct viral invasion of renal tissues exists,,. Notably, most patients who developed complications had coexisting medical co-morbidities. Laboratory findings on admission may include leukopenia, lymphopenia, thrombocytopenia, and elevated lactate dehydrogenase levels. MERS-CoV can also cause severe pneumonia with acute respiratory distress syndrome (ARDS), requiring mechanical ventilation and intensive care admission. To date, there is still a lack of surgical and pathological information from patients infected with MERS-CoV, which hampers full understanding of the pathogenesis. Lastly, co-infection with other respiratory viruses and with community-acquired bacteria has been also reported in MERS-CoV patients,,.
OHFV distribution is restricted to western Siberia (Figure 1). The main vector of OHFV is the meadow tick, Dermacentor reticulatus, which can also transmit the virus to humans. However, humans are mainly infected after contact with infected muskrats (Ondatra zibethicus) which are very sensitive to the infection and often succumb to the infection. Muskrats develop high viremia which can last for several weeks. Human infection occurs through contact with urine, feces, and blood. Secretion of OHFV in unpasteurized goat milk has been reported but no milk-borne outbreaks have been observed. The exact number of annual cases are uncertain because of misdiagnoses and unreported cases, but 165 cases were reported between 1988 and 1997. OHFV may cause a biphasic disease; the initial phase is characterized by high fever, bleeding from the nose, mouth, and uterus. Thirty to fifty percent of the cases experience a second phase characterized by high fever and reappearance of the symptoms from the initial phase. Case fatality rates range from 0.5 to 2.5%. No antiviral treatments are available against OHFV, instead treatment is focused on supportive care to minimize hemorrhage and other complications.
Leptospirosis is contracted either through direct contact with infected animal urine, or urine-contaminated water. It can be found worldwide, but is predominantly found in tropical and subtropical countries (during rainy season). Those taking part in water sports are most at risk (an outbreak was reported among canyoning participants in Martinique, France). Increased cases are also found in rural parts of a country where drinking water can be easily contaminated with the bacteria; for example, where wells have been poorly constructed. Lately, there has been an increase in the number of cases noted in Europe, with 97 cases identified in the Netherlands in 2014 (4.6-fold increase in comparison to previous years). Dutch tourists reported 33 cases of leptospirosis, and most of these tourists acquired the disease in Thailand.
The clinical course of leptospirosis is variable, with symptoms from myalgia to fever with cough and shortness of breath. Weil’s disease is its severest form and may develop in 1–5% of cases. Patients progress from mild flu-like symptoms to signs of organ failure (jaundice and spontaneous bleeding).
Where there is a high degree of clinical suspicion for leptospirosis, treatment should be instigated. Diagnosis is serological (via microscopic agglutination test [MAT] for antibodies or PCR urine antigen test) but it may take around 10 days after the onset of symptoms for these tests to become positive. In early mild disease, penicillin and tetracycline antibiotics are effective. Where the clinically more severe Weil’s disease is manifest, patients may require organ support, and there is little evidence that antibiotic use is of any benefit at this stage. In 2014, there were a total of 76 confirmed cases of leptospirosis in England and Wales, of which 22 were acquired overseas; the majority of these were related to recreational water exposure.
CEPICoalition for Epidemic Preparedness InnovationsEIDsEmerging Infectious DiseasesMERS-CoVMiddle East Respiratory Syndrome coronavirusR&Dresearch and developmentWHOWorld Health Organization
Abnormalities in chest radiography are found in most COVID-19 patients and featured by bilateral patchy shadows or ground glass opacity in the lungs. Patients often develop an atypical pneumonia, acute lung injury, and acute respiratory distress syndrome (ARDS) 34. When ARDS happens, uncontrolled inflammation, fluid accumulation, and progressive fibrosis severely compromise the gas exchange. Dysfunction of type-I and type-II pneumocytes decreases the surfactant level and increases surface tension, thus reducing the ability of the lungs to expand and heightening the risk of lung collapse 53,54. Therefore, the worst chest radiographic findings often parallel the most severe extent of the disease 55.
Many patients infected with SARS virus develop pneumonia. Suffocation while breathing will increase, and patient requires mechanical respirator for respiration. SARS will become lethal in a few cases, frequently due to respiratory failure. Other possible problems include cardiac and liver failure. Persons older than 60 years of age—particularly those who have complications such as diabetes or hepatitis—are at greater risk of severe complications (Koren et al., 2003, Müller et al., 2012).
Streptococcus pyogenes (Group A streptococcus) is a common pathogen responsible for a number of human suppurative infections, including pharyngitis, impetigo, pyoderma, erysipelas, cellulitis, necrotizing fasciitis, toxic streptococcal syndrome, scarlet fever, septicemia, pneumonia and meningitis. It also causes non-suppurative sequelae, including acute rheumatic fever, acute glomerulonephritis and acute arthritis. Scarlet fever, characterized by a sore throat, skin rash and strawberry tongue, is most prevalent in school children aged four to seven years old. This disease was listed as a notifiable disease in Taiwan until 2007; as such, all cases of scarlet fever had to be reported to the public heath department. According to our records, however, only 9% of the medical centers, regional hospitals and district hospitals in central Taiwan reported cases of scarlet fever to the health authorities between 1996 and 1999. The number of scarlet fever cases is therefore likely to be significantly underreported. Scarlet fever outbreaks frequently occur in young children at day-care centers, kindergartens and elementary schools and also occur in adults upon exposure to contaminated food.
Genotyping bacterial isolates with various methods is frequently used to compare the genetic relatedness of bacterial strains and provides useful information for epidemiological studies. In a previous study, we used emm (gene of M protein) sequencing, vir typing and pulsed-field gel electrophoresis (PFGE) typing to analyze a collection of streptococcal isolates from scarlet fever patients and used these data to build a DNA fingerprint and emm sequence database for long-term disease surveillance. Vir typing has since been abandoned in our lab because it has lower discriminatory power than PFGE and the protocol is difficult to standardize with conventional agarose gel electrophoresis. In contrast, the PFGE protocol for S. pyogenes has been standardized in our laboratory, and a second enzyme, SgrAI, has been found to replace SmaI for analysis of strains with DNA resistant to SmaI digestion. Since PFGE is highly discriminative and emm sequencing provides unambiguous sequence information regarding emm type, we adopted these two genotyping methods to characterize streptococcal isolates and build a Streptococcus pyogenes DNA fingerprint and sequence database for the long-term study of scarlet fever and other streptococcal diseases.
The number of scarlet fever cases in central Taiwan fluctuated greatly between 2000 and 2006. Relative to the number of scarlet fever occurrences in 2000, occurrences increased in 2001 and doubled in 2002, but dramatically dropped in 2003. The number of occurrences increased again since 2004. In this study, we characterized 1,218 isolates collected between 2000–2006 by emm sequencing and PFGE. The bacterial genotyping data and the epidemiological data collected via the Notifiable Disease Reporting System (established by Taiwan Centers for Disease Control (Taiwan CDC)) were used to examine the significant fluctuation in the number of scarlet fever cases between 2000 and 2006.
Clustered onset often happens in the same family or from the same gathering or vehicle such as a cruise ship. Patients often have a history of travel or residence in Wuhan or other affected areas or contact with infected individuals or patients in the recent two weeks before the onset 50. However, it has been reported that people can carry the virus without symptoms longer than two weeks and cured patients discharged from hospitals can carry the virus again 51, which sends out an alarm to increase the time for quarantine.
Human coronaviruses (HCoV) were first described in the mid-1960s. HCoV is an enveloped RNA virus with a single chain and positive polarity. The name “corona” comes from the crown-like spikes on the surface of the virus. Four major subgroups are known as follows: alpha, beta, gamma and delta. Subtypes of coronaviruses circulating in humans (HCoV-229E, HCoV-OC43, HCoV-NL63 and HKU1-CoV) are mostly viruses that cause colds. Coronaviruses are zoonotic viruses that infect many mammals and birds. There are many coronaviruses that have not been transmitted to humans yet but are detected in animals. Before the virus (most likely a bat virus) gained the ability to infect humans, it jumps an intermediate host as occurred in previous outbreaks. It has been revealed that for emerge of SARS-CoV (Severe acute respiratory syndrome), civet cats played an imported role for transmission of disease to humans, whereas one-humped camels played an intermediate host for MERS-CoV (Middle East Respiratory Syndrome). SARS-CoV was first defined in February 2003 in Asia (Guandong, China) and has spread to more than two dozen countries in North and South America, Europe and Asia. In about eight months, 8098 people are infected, and 774 people died. Since 2004, to our knowledge, there have been no new cases reported in the world. MERS- CoV also causes a severe respiratory disease with symptoms of fever, cough and shortness of breath. The disease was seen for the first time in September 2012 in Saudi Arabia, and all the patients with MERS- CoV had a history of travel or residence in the Arabian Peninsula and nearby countries. Outside the Arabian Peninsula, the disease was seen in the Republic of Korea in 2015. Again, the outbreak was associated with a traveler returning from the Arabian Peninsula. To date, 2494 people have been infected, and there 858 related deaths were reported related to MERS [2, 3].
General signs and symptoms comprise: rigor, feeling cold along with shivering, migraine, cough, sore throat, difficulty in breathing, muscular rheumatism, chest pain, kidney failure, pneumonia, giddiness, nausea and vomiting, dysentery, and stomach pain. It has been reported that abnormal symptoms comprising slight respiratory infection without pyrexia and diarrhea will occur before the development of pneumonia. Proper clinical decision should be followed for the diagnosis of patients suffering with MERS-CoV infection. It must be noted that immune-compromised people are thought to be at high risk to get infected by MERS-CoV.
According to phylogenetic differences, TBEV has been divided into three different subtypes, European, Siberian, and Far Eastern. The European subtype is mainly transmitted by Ixodes ricinus, whereas the Siberian and Far Eastern subtypes are primarily transmitted by Ixodes persulcatus. TBEV is found in central, eastern, and northern Europe and Asia (Figure 1) and correlates with the presence of infected ticks. Ixodes ricinus is found throughout Europe, whereas Ixodes persulcatus is found in Eastern Europe in the west, and China and Japan in the east.
TBEV is considered one of the most important arboviruses in central and eastern European countries and in Russia, with about 13,000 estimated human cases annually. In fact, over the last decade there has been an approximately 300% increase in the number of TBE cases in Europe, and TBEV is currently spreading into new regions in France, Sweden, Norway, and Italy. This increase is thought to be due to growth in population and spread of ticks, which is promoted by factors including climate change, social and political change, and changes in the land use. The increased expansion in Europe also poses an increased risk for the population engaged in outdoor activities.
TBEV is a zoonotic disease and the natural cycle of TBEV is dependent and maintained in a complex cycle involving ticks as the vector and reservoir of the virus and small rodents as hosts for ticks. Humans are not part of the natural transmission cycle of TBEV and are the incidental host when infected by a bite from an infected tick. Transmission through consumption of unpasteurized milk has also been reported for TBEV, as well as transmission via solid organ transplant.
During the tick bite, the virus is inoculated into the skin of the vertebrate host. The initial replication is believed to occur locally in the dendritic cells. This is followed by infection of the draining lymph nodes, resulting in the primary viremia and subsequent infection of the peripheral tissues, where further replication maintains the viremia for several days. The disease course of TBEV is biphasic; the initial phase is characterized by flu-like symptoms and is followed by a second phase involving CNS infection, with meningitis, encephalitis, or meningoencephalitis. The mortality rate of TBEV varies from 1 to 20% depending on the subtype, in which the European TBEV subtype has shown lower mortality rates compared to the Siberian and Far Eastern. Among the patients that experience neuroinvasive TBEV infection, approximately 25–40% of the survivors suffer from long lasting neurological sequelae. No antivirals are available for treatment of TBEV infection but there is an effective vaccine.
LGTV, which is closely related to TBEV, is found in south east Asia and Russia. LGTV has not been associated with human disease under natural infections although it shares 84% sequence identity with TBEV. Because of its avirulence in humans and close similarity to TBEV, LGTV is often used as a model virus for TBEV under biosafety level-2 conditions.
Despite the announcement of the successful eradication of smallpox in 1979, the last case of rinderpest in 2008 and the current campaigns to eradicate poliomyelitis and measles through mass-immunization programmes, we still face the prospect of emerging or reemerging viral pathogens that exploit changing anthropological behavioural patterns. These include intravenous drug abuse, unregulated marketing of domestic and wild animals, expanding human population densities, increasing human mobility, and dispersion of livestock, arthropods and commercial goods via expanding transportation systems. Consequently, the World Health Organization concluded that acquired immune deficiency syndrome, tuberculosis, malaria, and neglected tropical diseases will remain challenges for the foreseeable future.1 Understandably, the high human fatality rates reported during the recent epidemics of Ebola, severe acute respiratory syndrome and Middle East respiratory syndrome have attracted high levels of publicity. However, many other RNA viruses have emerged or reemerged and dispersed globally despite being considered to be neglected diseases.2,3 Chikungunya virus (CHIKV), West Nile virus (WNV) and dengue virus (DENV) are three of a large number of neglected human pathogenic arthropod-borne viruses (arboviruses) whose combined figures for morbidity and mortality far exceed those for Ebola, severe acute respiratory syndrome and Middle East respiratory syndrome viruses. For instance, for DENV, the number of cases of dengue fever/hemorrhagic fever is between 300–400 million annually, of which an estimated 22 000 humans die.4 Moreover, in the New World, within 12 months of its introduction, CHIKV caused more than a million cases of chikungunya fever according to Pan American Health Organization/World Health Organization, with sequelae that include persistent arthralgia, rheumatoid arthritis and lifelong chronic pain.5 Likewise, within two months of its introduction, to Polynesia, the number of reported cases exceeded 40 0006 and is currently believed to be approaching 200000 cases. Alarmingly, this rapid dispersion and epidemicity of CHIKV (and DENV or Zika virus in Oceania) is now threatening Europe and parts of Asia through infected individuals returning from these newly endemic regions. This is an increasingly worrying trend. For example, in France, from 1 May to 30 November, 2014, 1492 suspected cases of dengue or chikungunya fever were reported.7 Accordingly, this review focuses on the emergence or reemergence of arboviruses and their requirements and limitations for controlling these viruses in the future.
Middle East respiratory syndrome is caused by a novel coronavirus (MERS-CoV) first isolated in the Kingdom of Saudi Arabia in 2012 from the respiratory tract secretions of a Saudi businessman who died from viral pneumonia. Health officials first reported the disease in September 2012, when most cases originated in Saudi Arabia and, to a lesser extent, the United Arab Emirates (UAE). Subsequently, cases were identified in patients living outside the Arabian Peninsula and the Middle East, who were infected either during a stay in the Middle East or by close contact with an individual from an endemic country. Although the virus has no gender predisposition, most affected patients have been previously healthy men with a median age of 50 years.
Two years have passed since the initial description of the Middle East respiratory syndrome coronavirus (MERS-CoV), yet the epidemic is far from being controlled. The high case fatality rate, the recent steep increase in reported cases, and the potential to cause a global pandemic during the upcoming Hajj season are serious concerns. Although a wealth of information about the pathophysiology, proposed animal reservoir, and intermediate host has been revealed, many questions remain unanswered. We herein review MERS-CoV, covering its proposed origins, route of transmission, treatment options, and future perspectives.
This guideline presents the basic principles of antibiotic use for acute upper respiratory infections in adults aged 19 years or older, in consideration of South Korea's current state of affairs as of March 2017. Physicians should use this guideline as a reference while providing individualized care to patients, and not as a basis for universal application to all adult patients. This guideline cannot be used as a standard criterion to determine the adequacy of a clinician's final decision. Further, while this guideline may be used for personal care and educational purposes, it may not be used for commercial or care evaluation purposes. In cases where parties wish to use this guideline for purposes other than providing care and education, a written request should be submitted to the Committee to obtain written approval.
Infectious disease can be viewed as a play involving at least two characters: the pathogen and the host. While both roles can be represented by a great variety of performers, pathogens exhibit by far the highest variety and complexity. This review is about viral infections in animals. It aims first to give an idea of the enormous complexity and diversity of the existing infectious agents, emphasizing their extraordinary capacity for change and adaptation, which eventually leads to the emergence of new infectious diseases. Secondly, it focuses on the influence of the environment in this process, and on how environmental (including climate) changes occurring in recent times, have precise effects on the emergence and evolution of infectious diseases, some of which will be illustrated with specific examples. Finally, it describes the recent and dramatic expansion of two of the most important emerging animal viral diseases at present, bluetongue (BT) and West Nile fever/encephalitis (WNF), dealing with their relationship to climate and other environmental changes, particularly those linked to human activities, collectively known as “global change,” and that can be at least in part seen a consequence of the “globalization” phenomenon.
Pulmonary symptoms such as wheeze, breathlessness and hemoptysis and an eosinophilia in a returned traveller should prompt investigations for helminths. These infections may present as Loeffler’s syndrome (a result of larval migration through the lungs) or tropical pulmonary eosinophilia (hypersensitivity to lymphatic filarial worms). Specific to schistosomiasis infections, Katayama syndrome should be suspected in travellers returning from Africa or South East Asia with fresh water exposure presenting with fever, eosinophilia, dry cough and urticarial rash. Other rare pulmonary presentation of helminths infections (such as paragonimus, toxocariasis and dirofilariasis) should be considered depending on travel destination and incubation period. Treatment of these infections is generally straightforward once the causative helminths have been identified.
In 20% of hydatidosis (echinococcosis tapeworm) there are pulmonary infiltrations. The majority of cases are asymptomatic but following a leaking hydatid cyst in the liver, patients may present with pleuritic chest pain, breathlessness and cough; a ‘water lily’ sign may be seen on chest radiograph. Surgery (aspiration) and anti-parasitic drugs are required to fully treat the infection.
The first HCoV-229E strain was isolated from the respiratory tract of patients with upper respiratory tract infection in the year of 1966 27, and was subsequently adapted to grow in WI-38 lung cell lines 28. Patients infected with HCoV-229E presented with common cold symptoms, including headache, sneezing, malaise and sore-throat, with fever and cough seen in 10~20% cases 29. Later in 1967, HCoV-OC43 was isolated from organ culture and subsequent serial passage in brains of suckling mice 28. The clinical features of HCoV-OC43 infection appear to be similar to those caused by HCoV-229E, which are symptomatically indistinguishable from infection with other respiratory tract pathogens such as influenza A viruses and rhinoviruses 28.
Both HCoV-229E and HCoV-OC43 are distributed globally, and they tend to be predominantly transmitted during the season of winter in temperate climate 2. Generally, the incubation time of these two viruses is less than one week, followed by an approximately 2-week illness 28. According to a human volunteer study, healthy individuals infected with HCoV-229E developed mild common cold 30. Only a few immunocompromised patients exhibited severe lower respiratory tract infection.
SARS, also known as “atypical pneumonia”, was the first well documented HCoV-caused pandemic in human history and the etiological agent is SARS-CoV, the third HCoV discovered 14,15. The first case of SARS can be traced back to late 2002 in Guangdong Province of China. The SARS epidemic resulted in 8,096 reported cases with 774 deaths, spreading across many countries and continents. Apart from the super-spreaders, it was estimated that each case could give rise to approximately two secondary cases, with an incubation period of 4 to 7 days and the peak of viral load appearing on the 10th day of illness 14,15.
Patients infected with SARS-CoV initially present with myalgia, headache, fever, malaise and chills, followed by dyspnea, cough and respiratory distress as late symptoms 14,15. Lymphopenia, deranged liver function tests, and elevated creatine kinase are common laboratory abnormalities of SARS 14,15. Diffuse alveolar damage, epithelial cell proliferation and an increase of macrophages are also observed in SARS patients 31. Approximately 20-30% of patients subsequently require intensive care and mechanical ventilation. In addition to lower respiratory tract, multiple organs including gastrointestinal tract, liver and kidney can also be infected in these severe cases, usually accompanied with a cytokine storm, which might be lethal particularly in immunocompromised patients. The virus was first isolated from the open lung biopsy of a relative of the index patient who travelled to Hong Kong from Guangzhou 14,15. Since then, tremendous efforts have been dedicated to HCoV research.
A novel coronavirus has spread through China, originating from the city of Wuhan and has caused many deaths so far. It is a highly contagious virus that has spread rapidly and efficiently. Coronavirus disease 2019 (COVID-19) is caused by a virus (SARS-CoV-2) from the same family as the lethal coronaviruses that caused severe acute respiratory syndrome (SARS-CoV) and Middle East respiratory syndrome (MERS-CoV). COVID-19 is a relatively large virus (120 nm) and is enveloped, containing a positive-sense single-stranded RNA. The virus is transmitted through direct contact with the infected person’s respiratory droplets (coughing and sneezing), as well as contact with infected surfaces. COVID-19 virus can survive for days on surfaces, but a simple disinfectant can eliminate this. COVID-19 signs and symptoms include fever, cough, and shortness of breath. In more severe cases, infection can lead to pneumonia, serious respiratory problems and ultimately, fatalities. Thousands of people have been reported to have been infected with the virus so far. Apart from China, other cases of the disease, also known as COVID-2, have been reported in several countries, including Thailand, South Korea, Japan, Taiwan, Australia, Iran, and the United States. According to the Worldometer, as of 10th March 2020, there are over 114,430 identified cases of COVID-19 worldwide in 115 countries and territories.
Of these 115 countries, South Korea and Iran (outside of China) have the largest epidemic of COVID-19 and Italy, France and Spain are the countries with a major epidemic of COVID-19 in Europe. COVID-19 spreads mainly from person-to-person during the latency period before the symptoms appear. There is much more to learn about the spread and severity of COVID-19. COVID-19 can cause mild flu-like symptoms, including fever, cough, dyspnea, myalgia, and fatigue, while more serious forms can cause severe pneumonia, acute respiratory distress syndrome, septic shock, and organ failure, which can lead to death. Without a vaccine for COVID-19, transmission of the virus can be reduced with early detection and patient quarantine. There is epidemiological and clinical evidence to suggest a number of novel compounds, as well as medicines licensed for other conditions, that appear to have potential efficacy against COVID-19. However, in the absence of a safe and effective vaccine or medicine, reducing viral transmission is the only strategy available where general education, and implementing the appropriate prevention and control is key. Precautions can help suppress the risk of infection, such as washing the hands frequently with soap and water or an alcohol-based disinfectant gel, coughing into the elbow or a folded napkin/tissue, avoiding close contact with those who have symptoms, and self-isolating, but medical help must be sought if difficulty in breathing is experienced.
COVID-19 can be diagnosed with diagnostic test kits and imaging techniques such as chest X-ray and pulmonary CT scans that facilitate early diagnosis of pneumonia in patients with COVID-19 [10–12].
The case fatality rate (CFR), is a measure of the ability of a pathogen or virus to infect or damage a host in infectious disease and is described as the proportion of deaths within a defined population of interest, i.e. the percentage of cases that result in death. CFRs confers the extent of disease severity and CFR is necessary for setting priorities for public health in targeted interventions to reduce the severity of risk. Initial studies reported an estimation of 3% for the global CFR of COVID-19. Estimating CFR from country-level data requires assessment of information about the delay between the report of the country-specific cases and death from COVID-19, as well as underestimating and under-reporting of death-related cases, which may not be known. Given the importance of CFR and recovery rate (RR), in this current study the CFR and RR of different countries during a COVID-19 ongoing pandemic was observed using up-to-date country-level data.
Dengue virus (DENV) is a single-stranded, positive-sense RNA virus that belongs to the Flaviviridae family. There are four different serotypes of DENV. DENV is transmitted by Aedes aegypti and Aedes albopictus mosquitoes, and DENV infection causes dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). DSS is fatal in 1%–2.5% of cases with intensive treatment, and the mortality rate increases to >20% in the absence of proper treatment. Thus far, DENV infection has not been reported in South Korea, except in patients who have traveled to endemic areas, such as Asia-Pacific, Central and South America, and Africa, which are the major sited of dengue fever outbreaks. According to the World Health Organization, 40% of the world population lives in high-DENV areas. An estimated 390 million people are infected with DENV, and about 20,000 of them die each year. In 2014, 113 cases of dengue fever were reported in Yoyogi park in central Tokyo. Similarly, in Europe, from 2012 to 2013, more than 3,000 people were infected with DENV in Portuguese Madeira on the Atlantic Ocean. In addition, 2 and 17 cases of dengue fever in persons who had no previous travel abroad were reported in France and Croatia, respectively, which were the first known cases of self-occurrence in Europe since 1928 and suggest the possibility of a future DENV epidemic. A. aegypti and A. albopictus, which spread DENV, mostly inhabit the tropics and subtropics. These mosquitoes also carry several other infectious viruses, such as Chikungunya, West Nile fever, and yellow fever viruses, which have already been imported into Europe and the Americas by cargo ships and airlines. In 2013, subtropical mosquitoes were found in Jeju Island, South Korea. Based on their genome sequence, these mosquitos were identified as a strain of A. albopictus, a species which is known to transmit DENV, from Vietnam. Until now, all cases of DENV infection in Korea have been shown to be imported, and >95% of patients had returned to Korea after being infected in Southeast Asia or South Asia. However, as the domestic climate becomes more subtropical, these subtropical insects can survive much longer, and the possible occurrence of subtropical mosquitoes may result in an influx of DENV in South Korea.
The immunology and pathology of DENV have not yet been elucidated, and this has limited the development of vaccines and effective therapeutics. Since 1940, when the development of DENV vaccines and treatments began, preclinical testing has not provided sufficient evidence for efficacy or accurate toxicity profiles at the clinical trial stage. Dengvaxia, the first DENV vaccine (developed by Sanofi), is a quadrivalent vaccine that was marketed in five countries, including Brazil, beginning in June 2016. However, its efficacy is only about 60%, which is less effective than that of other vaccines for diseases such as measles and poliomyelitis, which are more than 95% effective. Children under the age of 9 years and adults over the age of 45 years, the main victims of dengue fever, are not eligible to receive Dengvaxia due to unexplained side effects. In addition, it has been shown to have insufficient effects on serotype 2 infection due to interference between serotypes. Furthermore, a component of the vaccine, the non-structural protein of the yellow fever virus, induces a T-cell reaction to yellow fever rather than an antibody response to DENV. A clinical trial of about 30,000 people conducted in 10 countries showed that the vaccine may cause serious symptoms in patients. The different clinical outcomes of vaccine administration, such as low efficacy and unexplained side effects, appear to result from the lack of an established disease model for testing the safety and efficacy.
Almost 120 years have passed since Walter Reed, James Carroll, Aristides Agramonte, and Jesse Lazear established that yellow fever is caused by a filterable infectious agent which is transmitted by the bite of a mosquito, then known as Stegomyia fasciata (Aedes aegypti). Lazear, who like his colleagues, had been stationed by the US Army in Cuba to study the disease, died of yellow fever in September 1900 after being exposed experimentally to mosquitos that had fed on sick patients. At about the same time in South Africa, James Spreull and Sir Arnold Theiler demonstrated that bluetongue disease of sheep is caused by an “ultravisible” agent that could be transmitted by the injection of an infected serum. Epidemiological evidence suggested that the agent was vector-borne, and it was subsequently shown by R.M. du Toit that the disease occurred in sheep inoculated experimentally with suspensions of wild-caught biting midges (Culicoides imicola). These and other seminal discoveries precipitated a century of research into vector-borne and zoonotic viral diseases, resulting in the discovery and isolation of many hundreds of novel viruses from insects or vertebrate hosts. Some were identified as important human or veterinary pathogens. Many other viruses were archived in reference collections, with only basic characterization of their biological or molecular properties. In recent years, the advent of next generation sequencing (NGS) has transformed this situation. Complete genome sequences are now available for many of the archived isolates, allowing more accurate taxonomic assignments, analysis of their phylogenetic and evolutionary relationships with other viruses, and evaluation of the potential risks they may present to humans and wild or domestic animal populations. NGS has also opened the door to viral metagenomics, which has greatly increased the pace of new virus discovery from a wide range of hosts, usually with complete or near-complete viral coding sequences, but no virus isolate and minimal biological data. This has presented both opportunities and challenges for virologists and epidemiologists, as well as viral taxonomists, evolutionary biologists, and bioinfomaticians. Sadly, this technological revolution has been accompanied by a period of progressive disinvestment in training in classical virology. In this review, we recall the rich history of the discovery of arboviruses and other zoonotic viruses in various settings around the world and the many outstanding scientists who have contributed to the endeavour. We also consider the impacts of NGS and metagenomic analysis, and the implications of these new technologies for the future of this important field of research.
Human coronaviruses (HCoVs), which are enveloped RNA viruses belonging to the Coronaviridae family, are associated with a wide spectrum of respiratory diseases. HCoV infections occur mainly in the winter-spring season. Thus far, six types of HCoV have been discovered in humans: HCoV-229E, HCoV-OC43, HCoV-NL63, HCoV-HKU1, severe acute respiratory syndrome coronavirus (SARS-CoV), and the Middle East respiratory syndrome coronavirus (MERS-CoV).
HCoV-229E and HCoV-OC43 were first identified in 1967 as the cause of upper and mild respiratory tract infections. During 2002 and 2003, SARS-CoV caused a worldwide epidemic, concluding in 8273 confirmed infections with a fatality rate of 9%; beside a few zoonotic cases and laboratory-acquired infections in December 2003 and in 2004, there have been no SARS-CoV transmitting within the human population after July 2003. SARS-CoV infection results in sudden onset of flu-like syndrome which includes fever, dry cough, and non-respiratory symptoms e.g., diarrhea, myalgia, headache and chills/rigors. In 2004, HCoV-NL63 was isolated from a 7-month-old child suffering from bronchiolitis and conjunctivitis. Its distinctive genomic features were important in identifying seven additional HCoV-NL63-infected individuals suffering from respiratory illness. In 2005, HCoV-HKU1 was isolated from patients with pneumonia and was defined as a new group of HCoV, featuring the lowest G + C content (32%) among all coronaviruses with a known genome sequence. MERS-CoV was first identified in the Kingdom of Saudi-Arabia in September 2012. Dromedary camels are considered a possible source of MERS-CoV infection, since MERS-CoV neutralizing antibodies were found in camels from the Spanish Canary Islands, Oman, and Egypt. Until April 2014, the World Health Organization (WHO) reported a total of 261 laboratory-confirmed MERS-CoV cases, resulting in 93 deaths. Of these, 145 were reported in Saudi Arabia and United Arab Emirates. Recently a major MERS-CoV outbreak was reported in the Republic of Korea, with 186 infected individuals, resulting in 38 deaths. At the end of May 2018, a total of 2220 laboratory-confirmed cases of MERS-CoV, including 790 associated deaths were reported globally; 1844 cases of these were reported from Saudi Arabia.
In this study, we analyze respiratory samples that were collected from patients presenting influenza-like illness (ILI) in a hospital and in the community in Israel during 2015–2016, for the presence of all known types of HCoV.