Question:

A 4-year-old boy is brought to the office due to hoarseness. The parents report that he has had worsening hoarseness for the past year, and his voice now sounds very raspy and rough. Flexible laryngoscopy is performed and shows bilateral lesions on the true vocal cords. Removal of these lesions is performed via direct laryngoscopy. Histopathologic analysis shows a fibrovascular core with benign squamous cells. The physician explains to the parents that this is likely due to a viral infection acquired through which of the following routes of transmission?

Arthropod vector

Direct droplet

Indirect contact

Vertical direct contact

Waterborne

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Recurrent respiratory papillomatosis
Etiology	HPV serotypes 6 &11 Vertical direct spread (in infants/children) Sexual contact or reactivation of vertically spread virus (in adults)
Histopathology	Infection of squamous mucosa Fibrovascular core with benign squamous cells
Clinical manifestations	Hoarseness Respiratory distress Verrucous, polypoid growths in clusters most commonly on TVCs
HPV = human papillomavirus; TVCs = true vocal cords.

This child has vocal fold lesions that histologically demonstrate a fibrovascular core with benign squamous cells, which is consistent with laryngeal papillomas due to recurrent respiratory papillomatosis (RRP). These lesions are often warty or grape-like and, as with skin papillomas, have dark-red punctate areas corresponding to blood vessels.

Laryngeal papillomas are caused by human papillomavirus (HPV) subtypes 6 and 11, which are also the subtypes most likely to cause genital warts (ie, condyloma acuminatum). A mother with genital warts is the most important risk factor for developing RRP. An infection acquired from a patient's mother during pregnancy, delivery, or the first 4 weeks postpartum is called vertical transmission. HPV infection is often acquired via direct contact during passage through the birth canal. The incidence of RRP is decreasing significantly, which is likely due to increasing HPV vaccination (which typically includes serotypes 6, 11, 16, and 18) in future mothers.

(Choice A) Arthropods can carry an infectious agent from one host and transmit it to another (eg, Borrelia burgdorferi, West Nile virus); some infectious agents require maturation in the arthropod vector prior to being infectious to humans (eg, plasmodium).

(Choice B) Respiratory droplets are created when an infected person coughs, sneezes, or talks. These large respiratory droplets can contain viruses or bacteria (eg, diphtheria, pertussis, influenza) that can infect others nearby (ie, <2 meters).

(Choices C and E) Indirect contact transmission includes diseases that are airborne (eg, measles), and that spread through contaminated objects (eg, viral conjunctivitis), food (eg, Clostridium botulinum), or contaminated drinking water (eg, cholera).

Educational objective:
Vertical direct transmission of human papillomavirus subtypes 6 and 11 can cause recurrent respiratory papillomatosis, which results in wart-like growths most commonly on the true vocal cords.