Identification of virus

Prepared by:

Putri Shareen Binti Rosman

Types of viral infectionAcute infections

-relatively short duration with rapid discovery.

Most viruses that infect humans, such as those that cause routine respiratory infections (e.g., cold viruses, influenza viruses) and gastrointestinal infections (e.g., Rotaviruses, Noroviruses),skin infection(e.g.,Varicella zoster virus) cause acute infections. 

Types of viral infections

Persistent infections - Viruses continually present in the body. - Late complications following acute infections. Also

known as latent infection. Eg:HSV-1(fever blister),HSV-2(genital herpes). Chronic infection - the virus can be demonstrated in the body at all

times and the disease may be present or absent for an extended period of time.

- Eg: hepatitis B (caused by HBV) and hepatitis C (caused by HCV). 

Slow infections 

- are ones in which the infectious agents gradually increase in number over a very long period of time during which no significant symptoms are seen.

- Eg: include AIDS (caused by HIV-1 and HIV-2) and certain lentiviruses that cause tumors in animals.

Portals of entry and exit of viruses

Virus can enter into our body at many different sites and these are called portals of entry.

Respiratory Tract

Genitourinary Tract

Gastrointestinal Tract

Skin/Mucous Membrane

Transplacental (mother to fetus)

Blood

Modes of Transmission

The mechanism for transfer of an infectious agent from a reservoir to a reservoir to a susceptible host.susceptible host.

Dr.M.ElBashaar

Means of TransmissionFive Main Routes

DropletAirborneCommon Vehicle (Food, blood)Vector-borneContact

Direct ContactIndirect Contact (Objects)

Dr.M.ElBashaar

Sources and modes of transmission of infection

1. Person-to-Person Spread Skin-to-skin contact, clothes, (viral as HSV1) Droplets during coughing, sneezing (common

cold, flu, swine flu, smallpox,measles,SARS) Stool-to-mouth (fecal-oral) spread, usually via

dirty hands or utensils (hepatitis A,poliomyelitis)

Dr.M.ElBashaar

Sources and modes of transmission of infection

Sexually transmitted (gonorrhea, genital HSV2,

genital warts (human papillomavirus – HPV).Blood-to-blood contact by:

contaminated needles, usually by drug addicts or health workers (hepatitis B, C, AIDS)

blood transfusion (hepatitis B,C, AIDS, viral hemorrhagic fevers)

Vectors: rabies anthropod:mosquitoes (Malaria, Dengue,Yellow fever)

Dr.M.ElBashaar

Sources and modes of transmission of infection

Spread from mother to fetus during pregnancy (hepatitis B, C, HIV, HSV-1, HSV-2, rubella, varicella, bird flu).

Food poisoning is an infection of the gastrointestinal tract caused by microbes from contaminated food:Eg: Enterovirus

Dr.M.ElBashaar

Viral Diseases

Diseases caused by viruses has been known for thousand years ago.

Antibiotics are not effective in killing virusesCertain viruses are also linked to cancer in human

such as Hepatitis B (liver cancer),Epstein-Barr virus (Burkitt’s Lymphoma) and Human Papilomavirus (cervical cancer).

Important viral diseases

AIDS:Immune system failureCommon cold:Sinus congestionEbola:High fever,uncontrolled bleedingHepatitis A:Flu like symptom,swollen liverHepatitis B:Flu-like symptom,swollen liver.Influenza (flu):Fever,chills,sneezing,body aches.Mumps:Painful swelling of saliva glandsPolio:Fever,headachenstiff neck,paralysisRabies: Mental depression,madness,paralysis

SARS:High fever,headche,dry cough,death.Smallpox:Malaise,fever,blisters,blindnessYellow fever:Fever,weakness,yelllow skin.

RNA viruses (+ve sense)

Picornaviridae TogaviridaeFlaviviridaeRetroviridae

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RNA viruses (-ve sense)

ParamyxoviridaeRhabdoviridaeOrthomyxoviridaeFiloviridaeBunyaviridaeReoviridae (double-stranded)

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DNA viruses

Double – stranded•Adenoviridae•Herpesviridae•Poxviridae•Papovaviridae•Hepadnaviridae

Single – strandedoParvoridae

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Assignment 1

Per group have 4-5 per group = 16 groupsPresentation after CNY holiday Each group have 5 minutes for presentationRepresent 5% marks for assessmentExplain the genome content, viral morphology,

modes of transmission, infection in human,treatment.

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