Adenoviruses

---

---

 

 

There are 6 groups of adenoviruses with over 40 serotypes.

 

Transmission

Transmission is mainly through respiratory route but may also be transmitted through faecal-oral route.

 

Incubation period

The incubation period ranges between 5 to 8 days.

 

---

Clinical presentations

---

 

Conjunctivitis

Outbreak of conjunctivitis is common.

The group B Adenovirus can cause haemorrhagic conjunctivitis.

 

Pharyngitis

Pharyngitis is commonly seen in infants and children.

From all the adenoviruses, Group C is the most common pathogen that is associated with pharyngitis.

 

Pharyngoconjunctival fever

Pharyngoconjunctival fever is commonly seen in clusters.

It is mainly caused by Group B adenoviruses.

 

Pneumonia

Type 3 and 7 are associated with pneumonia in Immunocompetent and immunocompromised patients.

Infection with these types of adenoviruses is associated with significant mortality in children.

 

Gastrointestinal disorder

Group F is associated with diarrhoeal illness.

It mainly affects children.

It is difficult to isolate this group of adenoviruses.

The transmission is through faecal- oral route.

 

Adenovirus in Immunocompromised patients

Adenovirus infection in  immunocompromised patients causes high mortality.

The most common presentations are

Ø      Pneumonitis

Ø      Hepatitis

Ø      Haemorrhagic cystitis

Ø      Encephalitis

Ø      Disseminated infection

---

Investigation

---

 

Depending on the clinical presentation

CBC

CRP

LFT

Urine analysis

Chest x-ray

 

 

Diagnostic tests

Respiratory secretions or conjunctival swab for IF and virus isolation.

Serum for CFT but it is rarely used.

 

Stool and urine for Electron microscope

Stool for EIA. As group F, which is associated with gastrointestinal problems, can not be grown  on routinely used cell lines. Therefore EIA or PCR are used to detect these viruses.

 

Immunocompromised patients

Urine, stool, blood, biopsy or CSF are appropriate specimens for Adenovirus DNA PCR.

Respiratory secretions (NPA or BAL) for IF and virus isolation

Stool for EM, virus isolation or EIA.

                

 

---

Treatment

---

 

Treatment is not usually required.

 

Care for hospitalised patients

Patient isolation is very important.

Immunocompromised patient can be treated with Ribavirin or Cidofovir.

Reducing the level of immunosuppression in transplant patients is more effective than the use of antiviral.

As the mortality is very high in infant and very young children, severe adenovirus infection can be treated with antivirals even though their efficacy is questionable.

 

---

Prevention 

---

 

There is no specific measure that can be used to prevent infection.

Vaccine has been developed for some of the adenovirus types and have been used to immunise military personnel.