Chair of Medical Biology, Microbiology, Virology, and Immunology Picornaviruse Family Lecturer Prof. S.I. Klymnyuk
Picornaviruses are small (20-30 nm) and nonenveloped and contain a single-stranded RNA genome (MW 2-3 x 106). The nucleocapsid has cubic symmetry and contains 32 spherical subunits (capsomeres). Virus maturation takes place in the cytoplasm. Enteroviruses and rhinoviruses commonly infect humans. Enterovirus. Enteroviruses exist in many animals, including humans, cattle, pigs, and mice. Enteroviruses of human origin include the following: (1) Polioviruses, types 1-3. (2) Coxsackie viruses of group A, types 1-24. (3) Coxsackie viruses of group B, types 1-6. (4) Echoviruses, types 1-34. (5) Enteroviruses, types 68-71. Since 1969, new enterovirus types have been assigned enterovirus type numbers rather than being subclassified as coxsackie-viruses or echoviruses. The vernacular names of the previously identified enteroviruses have been retained.
Genera of Picornaviruses Enterovirus Polio Coxsackie A and B Echo Other enteroviruses Diseases of the human (and other) alimentary tract (e.g. polio virus) Rhinovirus Disease of the nasopharyngeal region (e.g. common cold virus) Cardiovirus Murine encephalomyocarditis, Theiler's murine encephalomyelitis virus Aphthovirus Foot and mouth disease in cloven footed animals Hepatovirus Human hepatitis virus A Others Drosophila C virus, equine rhinoviruses, cricket paralysis virus
Clinical Picornavirus Syndromes Diseases (Virus Type) Polioviruses (types 1-3) Undifferentiated febrile illnesses (types 1-3) Aseptic memingitis (types 1-3) Paralisis and encephalitic diseases (types 1-3) Coxsackievirus group A (A1-A, A-24)* Acute hemorrhagic conjunctivitis (type 24 variant) Herpangina (types 2-6, 8, 10, 22) Exanthem (types 4, 5, 6, 9, 16) Hand-foot-mouth disease (types 5, 10, 16) Aseptic memingitis (types 1, 2, 4-7, 9, 10, 14, 16, 22) Paralysis and encephalitic diseases (occasional types 4, 7, 9, 10) Hepatitis (types 4, 9)
Virus Diseases (Virus Type) Coxsackievirus group A (A1-A, A-24)* Upper and lower respiratory illnesses (types 9, 10, 16, 21, 24 variant) Lymphonodular pharyngitis (10) Infantile diarrhea (types 18, 20, 21, 22, 24 variant) Undifferentiated febrile illnesses (types 1-6) Pleurodinia (types 1-5) Pericarditis, myocarditis (types 1-5) Aseptic meningitis types (106) Paralysis and encephalitic diseases (occasional types 1-5) Severe systemic infection in infants, meningoencephalitis and myocarditis (types 1-5) Upper and lower respiratory illnesses (types 4, 5) Exanthem, hepatitis, diarrhea (types 5)
Virus Diseases (Virus Type) Echoviruses (1-7, 9, 11, 29-33)* Aseptic meningitis (many seroypes ) Paralysis and encephalitic diseases (occasional types 1, 2, 4, 6, 7, 9, 11, 14-16, 18, 22, 30) Exanthem (types 1-9, 11, 14, 16, 18, 19, 25, 30, 32) Hand-foot-mouth disease (19) Pericarditis, myocarditis (types 1, 6, 9, 19, 22) Upper and lower respiratory illnesses (types 4, 9, 11, 20, 22, 25) Neanatal diarrhea (types 11, 14, 18, 20, 32) Epidemic mialgia (types 1, 6, 9) Hepatitis (types 4, 9)
Virus Diseases (Virus Type) New enteroviruses Pneumonia and bronchiolitis (types 68, 69) Acute hemorrhagic conjunctivitis (type 70) Aseptic meningitis, meningoencephalitis Hand-foot-mouth disease (71) Hepatitis (type 72) Rhinoviruses (1-115) Upper and lower respiratory illnesses (types 1-115) Hepatovirus (Hepatitis A) Gastroenteritis and hepatitis A * Reclassification of coxsackievirus A23 as echovirus 9, echovirus 8 as 1, echovirus 10 as reovirus, echovirus 28 as rhinovirus type 1A, and echovirus 34 as coxsackievirus A24.
Properties of enteroviruses Property Enteroviruses Size (nm) Capsid form Polypeptide RNA type RNA molecular weight Acid Optimal temperature for growth(oC) Density in caesium chloride (g/m) 22-30 Icosahedral VP1, VP2, VP3, VP4 SS-PS 2000,000-2600,000 Stable* 37 1.34*
Epidemic Poliomyelitis Virus Poliomyelitis is an acute infectious disease that in its serious form affects the central nervous system. The destruction of motor neurons in the spinal cord results in flaccid paralysis. However, most poliovirus infections are subclinical. In spite of the fact that poliomyelitis is one of the most ancient contagious diseases, its infectious nature was ascertained only in 1905 by O. Wickman who investigated a poliomyelitis epidemic in Sweden. In 1908-09, K. Landsteiner and E. Popper proved poliomyelitis to be of viral etiology. They produced a febrile disease in monkeys by injecting an emulsion prepared from the spinal cord of a fatal case of poliomyelitis. The animals displayed typical manifestations of poliomyelitis accompanied with flaccid paralysis. The virus was isolated in tissue culture in 1949 by J. Enders.
Poliomielitis virus Poliomielitis virus
Polioviruses
Поліовіруси
POLIOMYELITIS “Picornavirus” 3 types: Poliovirus 1,2,3 Ingested, spread by faeco-oral route: Commoner in areas of poor sanitation Infants protected by maternal antibodies
Monkey’s cell culture
Virus Replication. After attaching to virus receptors (which seem to be controlled in humans by genes on chromosome 19). Poliovirus RNA serves both as its own messenger RNA and as the source of the genetic information. Viral protein is synthesized on polysomes held together by viral RNA. Guanidine in concentrations greater than 1 mM and 2-(alpha-hydroxybenzyl)-benzimidazole inhibit poliovirus multiplication in tissue culture. Guanidine acts by inhibiting the release of newly made viral RNA from the replicative complex.
Important Characteristics D or N antigen: Type specific (CFA) C or H antigen: Common antigen (CFA) Type 1-3
Resistance. The virus is extremely resistant to photodynamic inactivation. It survives in sterile water at room temperature for a period of more than 100 days, in milk for 90 days, in faeces in the cold for more than 6 months, and in sewage for several months. It withstands exposure to 0.5-1 per cent phenol solutions and remains viable for several weeks at pH 3.8-8.5. The poliomyelitis virus is sensitive to calcium chlorate lime, chloramine, formalin, potassium permanganate, and hydrogen peroxide solutions. It is rapidly killed on boiling.
Pathogenesis Source of infection: Apparent and subclinical patients Incubation: 7-14 days Pathogenesis: Only much less than 0.1% subjects exposed to polio virus form the flaccid paralysis
Transmission Fecal – oral route: poor hygiene, dirty diapers (especially in day-care settings) Ingestion via contaminated food and water Contact with infected hands Inhalation of infectious aerosols
Clinical Syndromes Asymptomatic illness: 90% Abortive poliomyelitis, the minor illness: 5% infected people Nonparalytic poliomyelitis or aseptic meningitis: 1%-2% of patients with poliovirus infections. Paralytic polio, the major illness: 0.1% to 2%of persons with poliovirus
Child with polio sequelae
Polio in the United States, 1952
Lab Diagnosis Definitive diagnosis is made by osolation of the virus from stool, CFS, oropharyngeal secretions Cell culture involves fibroblastic MRC-5 cells CPE is usually evident within 36 hours Serotyping is based on neutralization of CPE by standardized antisera using intersecting pool followed by specific sera. ELISA IFA neutralizing Test CFT
Immunity sIgA and neutralizing antibody (IgG, IgA, IgM) persist for life span
Progress Toward Polio Eradication: 1988 ~350,000 cases 1000 cases/day worldwide 125 endemic countries
Progress Toward Polio Eradication: 1998 6349 cases ~40 endemic countries
Progress Toward Polio Eradication: 2004 1267 cases <10 endemic countries ~10 re-infected countries
Wild Poliovirus*, 04 May 2004 to 03 May 2005 Wild virus type 1 Wild virus type 3 Wild virus type 1 & 3 Endemic countries Re-established transmission countries Case or outbreak following importation The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. WHO 2005. All rights reserved *Excludes viruses detected from environmental surveillance and vaccine derived polio viruses. Data in WHO HQ as of 03 May 2005
Prevention Both oral polio vaccine (OPV live, attenuated， Sabin, 1957) and inactivated poliovirus vaccine (IPV, Salk, 1954) are avilable ****IPV is used for adult immunization and Immunocopromised patients
Advantages and disadvantages of opv Effectiveness Lifelong immunity Induction of secretory antibody response similar to that of natural infection Possibility of attenuated virus circulating in community by spread to contacts (indirect immunization)(herd immunity) Ease of administration Lack of need for repeated boosters Disadvantages Risk of vaccine-associated poliomyelites in vaccine recipients or contacts Spread of vaccine to contacts without their consent Unsafe administration for immunodeficient patients
Advantages and disadvantages of IPV Effectiveness Good stability during transport and in storage Safe administration in immunodeficient patients No risk of vaccine-related disease Disadvantages Lack of induction of local (gut) immunity Need for booster vaccine for lifelong immunity Fact that injection is more painful than oral administration Fact that higher community immunization levels are needed than with live vaccine
IPV (Salk Vaccine) Field Trials, 1954
Albert Sabin
USA, 1961
Uttar Pradesh, India, 2000
Вакцинація
Properties of the Viruses COXSACKIEVIRUSES The coxsackieviruses comprise a large subgroup of the enteroviruses. They produce a variety of illnesses in human beings, including aseptic meningitis, herpangina, pleurodynia, hand, foot, and mouth disease, myo- and pericarditis, common colds, and possibly diabetes. Coxsackieviruses have been divided into 2 groups, A and B, having different pathogenic potentials for mice. Coxsackie B viruses are the most commonly identified causative agents of viral heart disease in humans. Properties of the Viruses General Properties: Coxsackieviruses are typical enteroviruses, with a diameter of 28 nm.
Features of coxsackievirus infection in the labortory Types Growth in MK Effect in cell culture sucking mice Coxsackie A virus 1-24 a + Paralysis Coxsackie B virus 1-6 + Spasticity MK , monkey kidney a Coxsackievirus A23 now classified as echovirus 9
Group A viruses produce widespread myositis in the skeletal muscles of newborn mice, resulting in flaccid paralysis without other observable lesions. Group B viruses may produce focal myositis, encephalitis, and, most typically, necrotizing steatitis involving mainly fetal fat lobules. The genetic makeup of inbred strains determines their susceptibility to coxsackie B viruses. Some B strains also produce pancreatitis, myocarditis, endocarditis, and hepatitis in both suckling and adult mice. Corticosteroids may enhance the susceptibility of older mice to infection of the pancreas. Normal adult mice tolerate infections with group B coxsackieviruses. However, severely malnourished or immunodeficient mice have greatly enhanced susceptibility.
Features of coxsackievirus infection in man Coxsackievirus A 1-24 Asptic meningitis Febrile illness Herpangina Hand-foot-and-mouth disease Coxsackievirus B 1-6 Neonatal disease Myocarditis, hepatitis Meningitis
Pathogenesis of enterovirus infection Replication in oropharynx Rhino,echo, coxsackie,polio Primary viremia Secondary viremia Target Tissue Skin Muscle Brain Meninges Liver Echo Coxsackie A Echo Coxsackie A, B Polio Coxsackie Echo Polio Coxsackie Echo Coxsackie
Clinical Findings. The incubation period of coxsackievirus infection ranges from 2 to 9 days. The clinical manifestations of infection with various coxsackie viruses are diverse and may present as distinct disease entities. A. Herpangina: This disease is caused by certain group A viruses (2, 4, 5, 6, 8, 10), There is an abrupt onset of fever, sore throat, anorexia, dysphagia, vomiting, or abdominal pain. The pharynx is usually hyperaemic, and characteristic discrete vesicles occur on the anterior pillars of the fauces, the palate, uvula, tonsils, or tongue. The illness is self-limited and most frequent in small children. B. Summer Minor Illnesses: Coxsackieviruses are often isolated from patients with acute febrile illnesses of short duration that occur during the summer or fall and are without distinctive features.
Герпангіна, Коксаки-А
Exanthems – Rubelliform rashes
C. Pleurodynia (Epidemic Myalgia, Bornholm Disease): This disease is caused by group B viruses. Fever and chest pain are usually abrupt in onset but are sometimes preceded by malaise, headache, and anorexia. The chest pain may be located on either side or substernally, is intensified by movement, and may last from 2 days to 2 weeks. Abdominal pain occurs in approximately half of cases, and in children this may be the chief complaint. The illness is self-limited, and recovery is complete, although relapses are common.
D. Aseptic Meningitis and Mild Paresis: This syndrome is caused by all types of group B coxsackieviruses and by coxsackie viruses A7, A9, and A24. Fever, malaise, headache, nausea, and abdominal pain are common early symptoms. Signs of meningeal irritation, stiff neck or back, and vomiting may appear 1-2 days later. The disease sometimes progresses to mild muscle weakness suggestive of paralytic poliomyelitis. Patients almost always recover completely from nonpoliovirus paresis. Early in aseptic meningitis, the cerebrospinal fluid shows pleocytosis (up to 500 cells/mcL) with up to 50% polymorphonuclear neutrophils.
E. Neonatal Disease: Neonatal disease may be caused by group B coxsackieviruses. with lethargy, feeding difficulty, and vomiting, with or without fever. In severe cases, myocarditis or pericarditis can occur within the first 8 days of life; it may be preceded by a brief episode of diarrhea and anorexia. Cardiac and respiratory embarrassment are indicated by tachycardia, dyspnea, cyanosis, and changes in the electrocardiogram. The clinical course may be rapidly fatal, or the patient may recover completely. The disease may sometimes he acquired transplacentally. Myocarditis has also been caused by some group A coxsackieviruses.
F. Colds: A number of the enteroviruses have been associated with common colds; among these are coxsackieviruses A10, A21, A24, and B3. G. Hand, Foot, and Mouth Disease: This disease has been associated particularly with coxsackievirus A16, but A4, A5, A7, A9, and A10 have also been implicated. Virus may be recovered riot only from the stool and pharyngeal secretions but also from vesicular fluid- The syndrome is characterized by oral and pharyngeal ulcerations and a vesicular rash of the palms and soles that may spread to the arms and legs. Vesicles heal without crusting, which clinically differentiates them from the vesicles of herpes- and pox-viruses. The rare deaths are caused by pneumonia.
Висипка, Коксакивіруси
Hand-foot-and-mouth disease Hand-foot-and-mouth disease: mostly coxackie A fever, malaise, sore throat, vesicles on bucсal mucosa, tongue, hands, feet, buttocks highly infectious resolution – 1w
Коксакиінфекція, везикули
H. Myocardiopathy: Coxsackie virus B infections are increasingly recognized as a cause of primary myocardial disease in adults as well as children. Coxsackieviruses of group A and echoviruses have been implicated to a lesser degree. In experimental animals, the severity of acute viral myocardiopathy is greatly increased by vigorous exercise, hydrocortisone, alcohol consumption, pregnancy, and undernutrition and is greater in males than in females. In human illnesses, these factors may similarly increase the severity of the disease.
I. Acute Hemorrhagic Conjunctivitis: Coxsackievirus A24 is one of the agents that can cause this disease (see below). J. Diabetes Mellitus: Serologic studies suggest an association of diabetes of abrupt onset with past infection by Coxsackievirus B4 and perhaps other members of the B group. Experimental studies support the findings in humans. Another picornavirus, encephalomyocarditis virus, induces lesions in mice in the pancreatic islets of Langerhans as well as an accompanying diabetes. K. Swine Vesicular Disease: The agent of this disease is an enterovirus that antigenically is related to Coxsackievirus B5. Furthermore, the swine virus can also infect humans.
Immunity. In humans, Nt and CF antibodies are transferred passively from mother to fetus. Adults have antibodies against more types of coxsackieviruses than do children, which indicates that multiple experience with these viruses is common and increases with age.
Properties of the Viruses ECHOVIRUSES The echoviruses (enteric cytopathogenic human orphan viruses) are grouped together because they infect the human enteric tract and because they can be recovered from humans only by inoculation of certain tissue cultures. Over 30 serotypes are known, but not all cause human illness. Aseptic meningitis, febrile illnesses with or without rash, common colds, and acute hemorrhagic conjunctivitis are among the diseases caused by echoviruses. Properties of the Viruses General Properties. Echoviruses are typical enteroviruses measuring 24-30 nm.
Important Characteristics Not produce diseases in sucking mice, rabbits, or monkeys; Cause aseptic meningitis, infantile diarrhea, Monkey kidney and human embryonated kidney cell culture
ЕСНО9, висипка
ЕСНО-19, висипка
RHINOVIRUS GROUP Rhinoviruses are isolated commonly from the nose and throat but very rarely from feces. These viruses, as well as coronaviruses and some reo-, adeno-, entero-, parainfluenza, and influenza viruses, cause upper respiratory tract infections, including the "common cold." General Properties: Rhinoviruses are picornaviruses similar to enteroviruses but differing from them in having a CsCI buoyant density of 1.40 g/mL and in being acid-labile. Animal Susceptibility and Growth of Virus. These viruses are infectious only for humans and chimpanzees. They have been grown in cultures of human embryonic lung fibroblasts (WI-38) and in organ cultures of ferret and human trachea! epithelium. They are grown best at 33 °C in rolled cultures.
Риновірус
Illness associated with recently identified enteroviruses Enterovirus 68 Pneumonia and bronchiolitis Enterovirus 69 Isolated from an ill person in Mexico Enterovirus 70 Acute hameorrhagic conjunctivitis Enterovirus 70, 71 Paralysis, meningo-encephalitis Enterovirus 71 hand-foot-and-mouth disease Enterovirus 72 Hepatovirus( Hepatitis A)