Human Metapneumovirus

Prof. Dr. Saad S Al AniSenior Pediatric Consultant

Head of Pediatric DepartmentKhorfakkan Hospital

Sharjah ,UAEsaadsalani@yahoo.com

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Human Metapneumovirus (hMPV)

hMPV is associated with a substantial number of upper respiratory infections (URI) and episodes of acute otitis media (AOM).

Williams JV, Wang CK, Yang CF, et al: The role of human metapneumovirus in upper respiratory tract infections in children: a 20-year experience.  J Infect Dis  2006; 193:387-395

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• hMPV was first described in 2001 by Dutch investigators. (1)

• It is a member of the Pneumovirus subfamily of the Paramyxoviridae that includes respiratory syncytial virus (RSV) .

(1)van den Hoogen BG, de Jong JC, Groen J, et al: A newly discovered human pneumovirus isolated from young children with respiratory tract disease.  Nat Med  2001; 7:719-724.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• It is pleomorphic with a lipid envelope.• Single-stranded RNA genome

(1)van den Hoogen BG, de Jong JC, Groen J, et al: A newly discovered human pneumovirus isolated from young children with respiratory tract disease.  Nat Med  2001; 7:719-724.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• These illnesses are neither clinically nor radiographically distinct from the same clinical syndromes caused by other common respiratory viruses.

• hMPV can cause severe infections in immunocompromised hosts

• Transmission of hMPV likely occurs via respiratory droplets and secretions, similar to RSV

van den Hoogen BG, de Jong JC, Groen J, et al: A newly discovered human pneumovirus isolated from young children with respiratory tract disease.  Nat Med  2001; 7:719-724.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• Clinical manifestations of hMPV infection are generally similar to those caused by other respiratory viruses and include:

* Bronchiolitis * Croup * Pneumonia * Asthma exacerbation.

Osterhaus A, Fouchier R: Human metapneumovirus in the community.  Lancet  2003; 361:890-891.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• Hospitalizations occur more common in children or adults with underlying conditions such as:

* Prematurety * Asthma * Immune compromisation * Cardiopulmonary diseases.

Williams JV, Tollefson SJ, Heymann PW, et al: Human metapneumovirus infection in children hospitalized for wheezing.  J Allergy Clin Immunol  2005; 115:1311-1312

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Bar in the image represents 10 nm.

Glycoprotein spikes are visible in viral membrane and extruded nucleocapsid is visible below

Human Metapneumovirus

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Epidemiology

• Annual epidemics during the late winter and early spring months in temperate locations

• The peak incidence of hMPV usually occurs 1 to 2 months later than the peak of RSV.

• The percentage of hMPV detection varies from 6% to 15% among patients with acute respiratory tract infection

•van den Hoogen BG, van Doornum GJ, Fockens JC, et al: Prevalence and clinical symptoms of human metapneumovirus infection in hospitalized patients.  J Infect Dis  2003; 188:1571-1577.

• Esper F, Martinello RA, Boucher D, et al: A 1-year experience with human metapneumovirus in children aged < 5 years. J Infect Dis 2004; 189:1388-1396•Osterhaus A, Fouchier R: Human metapneumovirus in the community.  Lancet  2003; 361:890-891.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• Peak age of hospitalization for hMPV occurs between 6 and 12 months of age

• hMPV-infected children have higher rates of underlying disease than RSV-infected children.

•Thanasugarn W, Samransamruajkit R, Vanapongtipagorn P, et al: Human metapneumovirus infection in Thai children.  Scand J Infect Dis  2003; 35:754-756

•Bosis S, Esposito S, Niesters HG, et al: Impact of human metapneumovirus in childhood: comparison with respiratory syncytial virus and influenza viruses.  J Med Virol  2005; 75:101-104.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Clinical Manifestations

* Upper respiratory tract symptoms, including: - Rhinorrhea - Cough - Fever. - Conjunctivitis - Vomiting, Diarrhea , Rash are occasionally reported

Noyola DE, Alpuche-Solis AG, Herrera-Diaz A, et al: Human metapneumovirus infections in Mexico: epidemiological and clinical characteristics.  J Med Microbiol  2005; 54:969-974

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

* Lower respiratory tract syndromes most frequently associated with hMPV infection are:

- bronchiolitis

- croup

- pneumonia

- asthma exacerbation. Noyola DE, Alpuche-Solis AG, Herrera-Diaz A, et al: Human metapneumovirus infections in Mexico:

epidemiological and clinical characteristics.  J Med Microbiol  2005; 54:969-974

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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• Infancy 1.Bronchiolitis 2.Pneumonia  3.Croup  4.Exacerbation of asthma  5. Upper respiratory tract infection  6.Acute otitis media

Clinical Manifestations at Various Ages

Takao S, Shimozono H, Kashiwa H, et al: Clinical study of pediatric cases of acute respiratory diseases associated with human metapneumovirus in Japan.  Jpn J Infect Dis  2003; 56:127-129.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Cont.

• Older children /adults 1. Croup  2. Laryngitis   3. Bronchitis   4. Asthma exacerbation   5. Pneumonia (elderly)   6.Exacerbation of chronic obstructive pulmonary disease (elderly)

Takao S, Shimozono H, Kashiwa H, et al: Clinical study of pediatric cases of acute respiratory diseases associated with human metapneumovirus in Japan.  Jpn J Infect Dis  2003; 56:127-129.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Diagnosis

• There is no commercially available rapid antigen test for hMPV

• In general, reliable diagnosis of hMPV currently depends on molecular techniques based on standard or real-time RT-PCR assays.

•Bellau-Pujol S, Vabret A, Legrand L, et al: Development of three multiplex RT-PCR assays for the detection of 12 respiratory RNA viruses.  J Virol Methods  2005; 126:53-63.

•Lopez-Huertas MR, Casas I, Acosta-Herrera B, et al: Two RT-PCR based assays to detect human metapneumovirus in nasopharyngeal aspirates.  J Virol Methods  2005; 129:1-7.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Treatment

• The majority of children infected with hMPV can be managed at home with supportive care.

• For hospitalized infants and children the primary therapies are supplementary oxygen and intravenous hydration.

• Bronchodilators and corticosteroids ?• Ribavirin and polyclonal human immunoglobulin?(1)

(1)Hamelin ME, Prince GA, Boivin G: Effect of ribavirin and glucocorticoid treatment in a mouse model of human metapneumovirus infection.  Antimicrob Agents Chemother  2006; 50:774-777.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Prevention

• Recombinant hMPV strains that lack various genes• Highly immunogenic, inducing neutralizing

antibodies and protection against challenge with wild-type hMPV.

• Several potential vaccine candidates are in development within 3 years of the discovery of hMPV,

•Tang RS, Mahmood K, Macphail M, et al: A host-range restricted parainfluenza virus type 3 (PIV3) expressing the human metapneumovirus (hMPV) fusion protein elicits protective immunity in African green monkeys.  Vaccine  2005; 23:1657-1667.

•Biacchesi S, Skiadopoulos MH, Yang L, et al: Recombinant human metapneumovirus lacking the small hydrophobic SH

and/or attachment G glycoprotein: deletion of G yields a promising vaccine candidate. J Virol 2004; 78:12877-12887.

04/12/23 Prof. Dr. Saad S Al Ani Khorfakkan Hospital ,Sharjah ,UAE

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Thank you