Gastroenteritis Viruses Dentistry Prof Dr Asem Shehabi Faculty

Gastroenteritis Viruses (Dentistry) Prof. Dr. Asem Shehabi Faculty of Medicine University of Jordan

Enteroviruses-1 § Enteroviruses group: family Picornaviruses, 71 Serotypes: Includes: Polioviruses, Coxsackieviruses, Echoviruses & Hepatitis A virus. § Virus structure: SS+ve RNA, Rigid Capsule consist of 4 different polypeptides (VP 1 -4), Responsible for Attachment, virus replication in cytoplasm & release new virus. § Pathogenesis: Attached to mucosa Respiratory or direct Small Intestines cells. . Replication in RT-lymph nodes & Peryes’ pathes. . Spread within 1 -3 weeks to blood & less to CNS. § General Characteristics: Survive for weeks/months at room Temp. & longer in cold water, fresh vegetation, Stable p. H 3 -9, Killed rapidly at > Tep. 60 C. . Widely distribution in Humans, Animals Feces. . Contaminate Water, Fresh Food. § Sporadic & epidemic infection. . Highly communicable. . Mostly through fecal-oral transmission.

Poliovirus-Rota virus Icosahedral symmetry

Human Enteroviruses-2 § Infections more common in developing countries. . refuge camps with Low standard of hygiene, lack of clean water supply. . frequently in Summer. § Most infections cause mild-asymptomatic enteritis. . watery diarrhea & fever. . Rarely severe/ Chronic Gastroenteritis/CNS diseases § Other Clinical Features: mild Pharyngitis, Skin rashes, Acute hemorrhagic conjunctivitis, Pneumonia. . CNS disorder. . Aseptic meningo-encephalitis, Mild paralysis, Hand-foot-mouth disease. . Mostly infected children. . less adults. . Most infections self-Limited. § General immunity: Humoral & mucosal lifelong Immunity to specific virus serotype. . Rare re-infection with same serotype. . Generally mild symptoms healthy persons

Poliomeylitis-1 § Poliovirses: Only human reservoir, 3 Serotypes, each with a slightly different capsid proteins antigens. . 50% RNA homology with other enteric viruses. . § All 3 types cause the same disease symptoms. . Type-1 associated more with Paralytic disease. § Epidemic outbreaks may include 2 to 3 types. . mostly cause mild human poliomeylitis in children. § All Polioviruses survive long in cold water & moist environment for Few weeks/months. . Relatively resistant to antiseptic/ disinfection agents compared to other enteric viruses. . § Poliovirus Infection: , Oral-Fecal Route. . Multiplies first oropharynx, Spread to local lymph nodes. . Second multiplication in the gut mucosa. . mesenteric lymph nodes. . Later virus spread to Blood & CNS. . Incubation 3 -21 Days

Poliomeylitis-2 § During acute /subclinical Infection period. . Virus is shed in large number in feces. . infect close contacts. . Mostly children under 5 -year. . Spread by contaminate water, fresh food & hands § Three Clinical Features: 1 -Asymptomatc Poliomeylitis: 99% young children, Mild clinical symptoms/ Influenza-Like. . often associated with mild fever & gastrointestinal symptoms for few days. . infection confirmed only by laboratory test. 2 -Abortive Poliomeylitis: 0. 5 -1% infected children develop minor non-specific illness. . Mild diarrhea, headache, sore throat, fever, Mild CNS symptoms like back pain, aseptic meningitis. § Both clinical forms resulted in rapid recovery within one week with developing long-live immunity. .

Poliomeylitis-3 3 -Paralytic Poliomeylitis: less 1% cases cause Aseptic meningitis. . 1/1000 Children. . 1/75 Adults. . Associated muscle weakness. . legs are affected more often than the arms The limb becomes floppy and weak. . A condition known as Acute Flaccid Paralysis. . due to destruction Lower motor neurons. . Inflammation the Gray matter of spinal cord. . may be associated with invasive & damage brain stem cells causing Bulbar Poliomeylitis. . This sever form very rare. . Virus damage brain and spinal neurons. . Painful muscle spasms. . Respiratory paralysis. . High mortality. § Polio maternal infection acquired late in pregnancy. . May cause mild Poliomyelitis § Natural Infection & following Polio-vaccination. . Specific Ig. A, Ig. G. . Permanent Long-live Immunity.

Flaccid Paralysis

Poliomeylitis-4 § 2 -Types Poliovaccines : § Inactivated Salk Poliovaccine (1956) Given Intramuscularly. . stable at room temperature. . still used in USA & Few countries. § Poliovaccine Sabin (1962): Oral attenuated life virus. . Inactivated by room & high Tep. . Vaccine should kept at refrigeration temp. . More used Worldwide. . Jordan § Both Contain 3 types Polioviruses: 4 -Doses divided (1, 2, 4, 6 Months) in association with Triple Vaccine. . Children should be free of Fever, Diarrhea before given the vaccine. . Otherwise immune response will not develop enough immunity.

Coxsakieviruses § Coxsakieviruses: Both groups common in human feces, contaminated water fresh food. . § Both groups cause invasion mucosa of respiratory & intestinal. . causing mild sore throat/ diarrhea or both. . Rarely spread to Blood, CNS. . Common Aseptic meningitis in infants & skin rash. . Epidemic outbreak § 90% asymptomatic mild infection. . develop immunity. § Coxsakieviruses Group A infections: 26 serotypes § 1 -Acute Hemorrhagic Conjunctivitis: highly contagious disease. . painful & swelling of eyelids. . Conjunctive Bleeding. . All ages § 2 -Herpangina: Mild to severe sore throat. . associated with painful small vesicular or ulcerative lesions on oral mucosa, soft palate, Persist few days-2 weeks.

2/ § Similar to Herpes simplex virus infection. . Mostly children. . Less other ages. § 3 -Hand-Foot-Mouth Disease: Fine macular skin rashes, Palm & Soles. . may spread to arms and legs fever. . Both mouth & skin ulceration. . Continue for 1 -2 weeks, mostly children. 4 -Hemolytic Uremic Syndrome (HUS): caused by certain serotypes of Coxsackie A and B Following RT infection & Viremia. . Rarely cause kidney damage or flaccid paralysis. § Coxsackie Group B: 6 serotypes. . infect the heart, pleura, pancreas, liver, causing febrile illness, myocarditis, pericarditis , hepatitis mostly in infants & immunosuppressed patients. § No Vaccine or Antiviral treatment, Interferon may help.

Coxsakieviruses Oral Ulcerations are common many times each year in persons of all ages without underling conditions

Echoviruses § Echoviruses (Enteric Cytopathgenic Human Orphan): 30 serotypes. . Generally less virulent & infectious than Coxsakieviruses. Common cause of acute febrile illness in infants and young children. . Poor hygiene § Clincal disease: Asymptomatic or mild Respiratory Infection mostly associated with contaminated fresh food & water. . May acquired in swimming pool. § Rare cases: Acute aseptic meningitis, Encephalitis , Hemorrhagic hepatitis, Myocarditis & Pericarditis , Hemolytic Uremic Syndrome mostly Children. . More severe diseases observed in newborn babies (neonatal infection) who have no maternal antibodies. . higly fatal. § Specific immunity develop against few serotypes. . No specific antiviral treatment or vaccines.

Rotavirus § Double-S RNA virus/Family Reoviridae. Common § § § Type A & C found in intestines human, animals, Birds. Rotavirus causes gastroenteritis. Symptoms include: Mild- severe diarrhea, vomiting, fever, and dehydration. Almost all children are likely to be infected before their first month birthday. Rotavirus causes more acute severe diarrhea in Infant. Children aged < 2 Years. . Rarely older children & adults. Common in Winter. . Incub. 2 -4 Days. . Accounted for 20 -50% of all diarrhea in infants. . High incidence with low standard of hygiene, hospitals & nurseries outbreaks. Chronic diarrhea common in malnourished infants. . Difficult to control. . High Infant Death in developing countries Immunity: Recently introduced vaccine. . Specific intestinal Ig. A Antibodies. . Protective ( 80 -90%). Lab. Diagnosis: Feces examination by Rapid Rota-Latex Test. Treatment: No specific drugs, Fluid Rehydration most important

Noroviruses & Other Caliciviruses § Noroviruses: Part of Calicivirus group. . SS+ve RNA, non-enveloped. . Widely distributed in polluted water with human and animal feces. . especially cattle, pigs, cats, chicken. . highly infectious pathogens. . Personal contact, food poisoning infections worldwide § Acute gastroenteritis / Enteritis in humans. . More in young children than adults. . Inflammation stomach & small- large intestines. . § Approximately 50% of all gastroenteritis outbreaks in developed countries are caused by Norovirus. . infant & children more susceptible than adults. . diarrhea may last few days. . Treatment oral dehydration. . No antimicrobial drugs. § Caliciviruses are similar in morphology, structure & epidemiology to norovirus.

2/ § Caliciviruses infection: Gastroenteritis or only watery diarrhea accompanied by abdominal cramps. . Some people also complain of headache, fever/chills, and muscle pains. . Symptoms usually last for 1 -2 days. § Astroviruses. . SS-Ve RNA, small, round viruses with a characteristic star-like appearance in the electron microscope. Found in intestines human & animal alone or with Rota & other enteric viruses. § Mostly causing Acute/mild diarrhea infant & young children. . Occasional outbreaks in schools, nurseries, camps, families all ages. . associated with cold food, fishes, Ice creams, cold water § All Enteroviruses infections develop specific intestinal antibodies & partial immunity. . Rarely reinfection within few months. . No vaccine. . Supportive treatment.