Chickenpox and Shingles

Human Diseases Caused by Viruses

• Viruses transmit through airborne particles, arthropods, direct contact, or animal interactions

Airborne Diseases Caused by Viruses

• Air does not support multiplying the viruses themselves
• Humans are the source, airborne viruses are expelled by coughing, sneezing, or speaking

Chickenpox and Shingles

• Chickenpox is a highly contagious skin disease primarily affecting children aged 2 to 7
• The causative agent of chickenpox is the enveloped DNA varicella-zoster virus (VZV)
• Chickenpox results from the initial infection
• Shingles is the reactivated form of chickenpox called herpes zoster
• Recognizing chickenpox, the immune system responds with humoral and cellular immunity
• The incubation period is approximately 10 to 23 days
• Small vesicles erupt on the face or upper trunk
• Vesicles fill with pus, then rupture, and become scab-covered
• Vesicles heal in about 10 days
• Itching also occurs
• Symptoms include an itchy rash with flat red spots turning to fluid-filled blisters
• Transmission occurs when humans acquire the virus through droplet inhalation
• Diagnosis is made by clinical assessment
• Detection involves varicella-zoster immunoglobulin M (IgM) antibody
• Detection involves VZV or VZV antigen by direct fluorescent antibody and PCR
• Detection involves a significant rise in serum IgG antibody levels to VZV
• Prevention includes an attenuated varicella vaccine ((Varivax) or the drug acyclovir (Zovirax or Valtrex)

Influenza

• Influenza is caused by negative-strand RNA viruses, family Orthomyxoviridae
• Influenza has three genera: Influenza A, B, C, but only types A and B cause human disease
• Infection is influenced by cold weather
• It is a major epidemic disease, causing worldwide pandemics due to animal reservoirs and crowding
• Annual immunization with inactivated virus vaccine is recommended, but immunity lasts 1-2 years
• Subtle protein changes (antigens) frequently occur in influenza viruses, called antigenic drift
• Antigenic drift is a small variation resulting from mutations of hemagglutinin and neuraminidase
• Antigenic shift is a large antigenic change through reassortment of genomes
• Antigenic shift occurs when two strains infect the same host cell and are incorporated into a new capsid
• Antigenic shift can cause major epidemics and pandemics
• Symptoms include nasal discharge, chills, fever (usually > 39°C), headache, malaise, cough, and aches
• Transmission occurs through the respiratory tract via respiratory droplets
• Diagnosis involves clinical assessment and Directigen FLU-A (EIA rapid test)
• Treatment includes a flu vaccine yearly, treatment for symptoms only, and neuraminidase inhibitors

Measles (Rubeola)

• Measles is caused by measles virus (MeV), an enveloped RNA virus
• Morbillivirus is the genus and Paramyxoviridae is and the family
• Measles is a highly contagious skin disease that is endemic worldwide
• It is preventable but is still a leading cause of death in young children globally
• South Africa has seen an increase in measles and rubella cases in 2024
• Measles enters the body through the respiratory tract or the eyes
• The incubation period for measles is 10 to 14 days
• Viral hemagglutinin (H) glycoprotein attaches to receptors on B and T cells
• Fusion of the viral envelope and host cytosol is prompted by the hemagglutinin
• MRNA is capped and polyadenylated in the cytoplasm
• Symptoms commonly include nasal discharge, cough, fever, and headache
• The virus enters through the respiratory tract or conjunctiva
• No specific treatment exists
• Attenuated vaccines protect against measles, mumps, rubella, etc

Mumps

• Mumps is an acute, generalized disease primarily in school-age children
• It is caused by the mumps virus, genus Rubulavirus, family Paramyxoviridae
• Symptoms include swelling and tenderness of the salivary (parotid) glands 16-18 days post-infection
• Complications include meningitis and orchitis (inflammation of testis)
• Mumps transmits through saliva and respiratory droplets entering the respiratory tract
• Diagnosis involves detecting mumps IgM antibody in serum
• Treatment focuses on symptomatic and supportive care
• A live attenuated vaccine provides prevention

Rubella (German Measles)

• Rubella is moderately contagious and primarily affects children ages 5-9
• It is caused by the rubella virus, an enveloped RNA virus, in the family Togaviridae
• It is disastrous in the first trimester of pregnancy causing fetal death or congenital defects
• Symptoms arise after a 12-23 day incubation period
• Characterized by a rash, lasting ~ 3 days, and mild fever
• The virus spreads through respiratory secretions
• A live attenuated rubella vaccine prevents/treats the condition

Smallpox (Variola)

• Smallpox is caused by Orthopoxviruses (species Variolavirus, family Poxviridaevirus)
• Smallpox no longer exists due to eradication
• Smallpox was the first disease for which there was a vaccine
• Humans are the only natural hosts of variola
• It is a potential bioterrorism agent
• Symptoms are an acute onset of a fever and distinctive rash
• Transmission is through direct, prolonged contact
• Also spreads through contact with infected bodily fluids or contaminated objects
• Vaccination (live Vaccinia virus) provides treatment

Viral Pneumonia

• Viral pneumonia is an acute viral infection of the respiratory system
• It is the most common cause of human disease
• Manifestations include rhinitis, tonsillitis, laryngitis, and bronchitis
• Coronaviruses are positive strand RNA viruses with crown-like spikes
• Virions are large (120-150 nm) with a helical nucleocapsid
• Large spikes protrude the envelope to aid attachment

SARS

• The first outbreak of SARS was in 2002 within the Guangdog province of China
• SARS causes life-threatening pneumonia in humans
• Clinical manifestations include viral pneumonia, rapid respiratory deterioration, fever, chills, etc
• SARS symptoms are viral pneumonia and rapid respiratory deterioration
• Humans introduced SARS through a bat virus from palm civets sold in a live game market
• Diagnosis involves real-time PCR
• Treatments include Ribavirin drugs, and interferon/lopinavir

MERS

• The first MERS case was discovered in Saudi Arabia in June 2012
• The incubation period for MERS is 2-14 days
• Symptoms are fever, cough, sore throat, and shortness of breath
• It is transmitted person-to-person
• MERS has zoonotic spread of camels to humans
• The diagnosis is real-time PCR

COVID-19

• In December 2019, Wuhan city, China saw a pneumonia of unknown cause
• Characterized as a new coronavirus causative agent of SARS-CoV2 by the WHO
• Symptoms are fever, cough, myalgia, and sputum production
• Individuals develop Acute Respiratory Distress Syndrome from respiratory infections
• Domestic animals are believed to be the intermediate animal source after bats
• COVID-19 can transmit by asymptomatic individuals through respiratory droplets
• Real-time PCR and antigen tests are used in diagnosis

RSV

• RSV, the Respiratory Syncytial Virus, is a cause of lower respiratory infections in infants
• Its name is from syncytium or multinucleated mass formation
• It is enveloped with virus-specific glycoproteins
• Glycoprotein G binds to the virus host
• Glycoprotein F permits viral envelope fusion
• Commonly presents as acute onset fever, cough, rhinitis, and nasal congestion
• Transmission occurs through direct contact with respiratory secretions
• The diagnostic tool is a rapid antigen test or RSV detection by reverse transcriptase PCR
• Treatments involve fluid replacement and fever reducers

Arthropod-Borne Diseases

• Arthropod-borne viruses (arboviruses) are transmitted by bloodsucking arthropods
• Arthropods include ticks, mosquitoes, and certain flies between vertebrate hosts
• It multiplies in arthropod tissues without causing disease in the arthropod itself
• Arboviruses can cause three clinical syndromes
• • Fevers of an undifferentiated type with or without a rash
• • Encephalitis (inflammation of the brain) is common with a high fatality rate
• • Hemorrhagic fevers - frequently severe and fatal
• Supportive treatment is the only option, as antiviral treatments do not exist
• Detection occurs via nucleic acid amplification and serology

Yellow Fever

• Yellow fever was the first human disease discovered to be caused by a virus
• It was also the first disease that insects were found to be spread it
• Yellow fever transmits through two methods
• • Human-to-human is carried by Aedes aegypti mosquitoes
• • Monkey-to-human transmissions are in sylvatic cycles in jungle regions
• Symptoms are fever and chills, headache and backache, nausea, and vomiting
• In severe cases, jaundice is experienced
• Lesions and hemorrhaging of the infected organs also occur
• Diagnosis tests for viral antigens or cultures the virus from blood samples
• Other diagnosis methods ELIS, Aantigen capture
• Treatment focuses on serological tests and symptomatic and supportive care with a live vaccine

Chikungunya

• The Chikungunya virus is a member of Togaviridae It is a positive-strand enveloped RNA virus
• Transmitted by Aedes aegypti and A. albopictus mosquitoes to humans
• Acute infections cause joint pain and swelling
• 7-10 day resolution is common, but varies
• Symptom are eye inflammation, myocarditis
• Treatment comes only for pain
• Fluids are recommended to drink

Direct Contact Diseases

• Direct contact diseases spread from person-to-person through physical contact

AIDS

• AIDS is caused by the human immunodeficiency virus (HIV)
• It was first described in 1981
• HIV is a positive-strand, enveloped RNA virus
• HIV-1 primarily causes AIDS, but HIV-2 is prevalent in African countries
• AIDS is transmitted through infected blood, semen, or vaginal secretions
• Intravenous drug users and heterosexual men and women are at risk
• Semen transmission can cause a 100,000-fold increase in virulence
• AIDS can cause symptoms of weight loss, swollen lymph glands, and lung infections
• The virus is transmitted: through sexual contact or blood
• Diagnosis is by HIV antibody rapid test
• HIV is countered by ART (antiretroviral) drugs to prevent HIV virulence
• Prevention includes sterilized needles for drugs
• Control includes treating infections

Cold Sores

• Fever blisters with fluid are typically found on the nose and lips
• Double-stranded DNA virus, Herpesvirus in enveloped
• Direct contact with epithelial cells cause fever
• Clinical test determine if fever
• Acyclovir, trifluridine and is an example.

Common Cold

• Infections are higher during winter
• Positive-strand RNA in Picornairdae
• Spread throught nasal secretion and close
• Nasal congestion is symptom
• Observation for diagnosis
• Rest and anti is treatment

Gential Herpes

• Herpes Simplex virus causes herpes
• Sex and birth transmission
• Blisters and fever is symptom
• Screening, blood and Direct fluorescense test
• Acyclovir is treatment.

Viral Hepatitides

• Inflammation of liver (recognised as Eleven)
• Two of herpes
• HBV cause Hepatitis B
• Enveloped virus DNA is contained
• Serology, Test and load tests are performed
• blood transmission
• Treatment :entecavvir

Hepatitis C

• Family Flaviviridae
• Infection comes through contacted blood
• Diagnosis of positive viral
• Vaccination is available

Hepatitis D

• Spread on HBV, (super infection)
• Testing is done
• Vaccination and antiviral is done

Warts

• Caused by P.Family
• Non-enveloped
• They are four types
• warts can be on skin for 1-6months
• Removal is completed by electro surgery
• Injection A interferon and is an example

Food and Water Borne Diseases

• Viral gastroenteritis is the inflammation of the stomach and intestines
• Major categories from adenoviruses, calicirviruses par echo
• Mild to severe diarhea
• Route for infection is fecal-oral for this condition
• oral fluid can be used
• HAV causes Hepatitis A
• Hepatovirus and Picornaviridae (Family)
• symptoms consist anerexoria, fever and nausea
• Transmission is through fecal material
• Tests can prove virus is in you
• Prevention against it needs a hepitits A vaccination

Hepatitis E

• Hepatitis E viris is HEV
• Symptoms for symptoms, anorexia is there
• Water transmitts
• Revese transcriptase and ELISA tests
• fluids is treatment

Poliomyelitis

• Poliovurus will caus the disease
• picornaviridae helps tranit
• the symtpoms is headache and fever
• drinking contaminated water
• Live/ killed vaccine provides better protection

Zoonotic Diseases

Ebola

• Ebola is a zoonotic RNA virus belonging to Arena, Bunyavi, Filo, and Pico families
• They are typically found in animal resevoirs
• Ebola can be contracted by bats, primates
• Spread happens through direct contact in fluids.
• Fluid and electrolyte treatment

Rabies

• Rabies results from rabies virus.
• In brain, produces negribodies
• Aerososls can transmit virus
• After exposure 2016 weeks. Anxiety will exist.
• Diagnosis tests are needed
• Vaccination post will stop symptoms.