Human Papillomavirus

By Patrick Guilfoile

Human papillomavirus (HPV) is the most common sexually transmitted infection, according to the Centers for Disease Control and Prevention. More than 40 types of HPV can infect the genital area. Certain strains cause genital warts; other strains cause cervical cancer or cancers of the vagina, penis, and anus. Vaccines are available to prevent certain types of HPV, and practicing safe sex by using condoms can help prevent transmission. Human Papillomavirus describes the symptoms, diagnosis, treatment, and prevention of human papillomavirus, the newest HPV research, and future prospects for controlling this disease.

Chapters include:

• What Is Human Papillomavirus?
• The Biology of Human Papillomavirus
• Treatment of HPV Infections
• Prevention of HPV Infection and Cervical Cancer
• Future Prospects and Concerns Regarding HPV and Cancer.

• Language: English
• Publisher: Chelsea House
• Release date: Sep 1, 2019
• ISBN: 9781438139432

Book preview

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Human Papillomavirus

Copyright © 2019 by Infobase

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Contents

Foreword

Acknowledgments

Chapters

What Is Human Papillomavirus

The History of Human Papillomavirus

The Biology of Human Papillomavirus

Treatment of HPV Infections

Prevention of HPV Infection and Cervical Cancer

Future Prospects and Concerns Regarding HPV and Cancer

Support Materials

Glossary

Further Resources

About the Author

About the Consulting Editor

Index

Foreword

The outbreak of Severe Acute Respiratory Syndrome (SARS) in the early part of the 21st century highlighted the significance of infectious disease outbreaks in the world today:  from a Chinese medical doctor who had become ill while treating patients with a clinically severe pulmonary syndrome in his home province, who then traveled to Hong Kong and stayed overnight in a hotel with international guests, the coronavirus that caused SARS spread around the world. The outbreaks that resulted, mostly in highly  industrialized countries, were typical of emerging infections in today’s globalized world.  Not only are these outbreaks serious risks to human health—often causing high mortality—they also have an effect on economies.  Fortunately the SARS outbreak was fully contained within six months – with a death toll just over 800.  But the SARS outbreaks also caused a severe shock to economies in Asia where travel, trade, and tourism came to a virtual standstill. 

Following the SARS outbreaks the International Health Regulations (IHR)—international law developed in the late 1960s to attempt to stop infectious disease at international borders—were revised.  Today the IHR provide requirements for a global response should infectious diseases cross national borders, and more importantly they require all countries to develop the public health capacity to help detect and stop infectious disease outbreaks where and when they occur. 

During the time of the revision of the IHR the related concept of global health security became an important political issue worldwide.  Its importance was highlighted by the 2013—2014 Ebola outbreaks in West Africa. Like SARS, Ebola virus infection spread across national borders to neighboring countries, and to highly industrialized countries far from the African continent.

The concept of global health security for persons living in industrialized countries with equitable access to health services is clear—it is about reducing their vulnerability to infectious disease threats that spread across national borders. 

But in many ways health security is like a chameleon that changes color depending on its environment. In addition to the collective health risk caused by the international spread of Ebola virus infection, health workers in West Africa, some infected with the Ebola virus, and Ebola-infected persons from communities they served, were forced to accept that their health care was not always effective, and not always accessible—that their own, individual health security was at risk. And many persons infected with the Ebola virus in West Africa died because their weak health systems collapsed, and care was not available to them, nor was it available to children and others who had nowhere to seek care for common infections such as malaria and other highly fatal tropical diseases.

The intertwining of collective and individual health security is a concept that must remain high on the political agenda as the IHR continue to serve as a global framework for collective health security, and as the world focuses its attention on universal health coverage, the key to realizing individual health security. At the same time the impact of deadly infectious disease outbreaks, and other outbreaks such as those caused by infections resistant to antimicrobial drugs, will remain a threat to collective and individual health security. This series of Deadly Diseases and Epidemics describes the past and present, and forecasts the future. It is important reading for anyone concerned about the spread of diseases in modern society.

David L.  Heymann, M.D.

Professor, Infectious Disease Epidemiology

London School of Hygiene and Tropical Medicine

Acknowledgments

I thank my wife, Audrey, for her support of my work on this project, and her willingness to listen to my descriptions of the latest interesting tidbits from an article or book about human papillomavirus, as I was researching this manuscript. I also appreciate her willingness to review a draft of the document. I thank my father, Thomas Guilfoile, for his keen proofreading skills.

Chapters

What Is Human Papillomavirus

At the age of 20, Jade Goody appeared on the U.K. reality TV show, Big Brother. Initially vilified by the public, based on her actions on the show, she ultimately became a celebrity, with her own TV series, perfume, and workout and diet DVDs. At the age of 26, while starring in another reality TV show, she learned she had cervical cancer, almost certainly resulting from a human papillomavirus infection. She became a regular fixture on talk shows and in other media, describing her struggles with cancer. This increased public awareness about cervical cancer and led to a frank discussion about death and dying, which many in Britain appreciated. Even with her substantial financial resources, Jade Goody died within 18 months of her diagnosis, after the cancer had spread throughout her body.¹  Although methods now exist to prevent most HPV infections that cause cervical cancer, and to diagnose cervical cancer at an early, treatable stage, about a quarter of a million women currently die from cervical cancer each year, worldwide.

Human papillomavirus (HPV) infection is the most common sexually transmitted disease, with an estimated 79 million people infected and 14 million new infections in the United States each year.² A report from the Centers for Disease Control and Prevention estimated that 45% of men and 40% of women in the U.S. had an active HPV infection during surveys conducted between 2011 to 2014.³ In the United States alone, the annual cost of identifying and treating HPV infections, and diseases caused by HPV infection, is about $8 billion.⁴ Worldwide, an estimated 300 million new cases of HPV infection occur each year.⁵

More than a third of the population age 18 to 59 were infected with genital HPV in 2014.

Source: Infobase.

About 40% of U.S. women are infected with HPV within two years of the time they first have sexual intercourse.⁶ A more global perspective found a wide variation in the prevalence of HPV infection in women in different countries. Worldwide, the prevalence of a woman having at least one of the tested HPV types is estimated to be about 10% ⁷ (Prevalence indicates the percentage of individuals with the infection at one specific point in time). However, individual studies of HPV prevalence in females ranged widely from 84% in one study from Jamaica to as low as 0.6% in one study from Iran⁸ The prevalence of HPV infections in men is generally higher, compared to women, with many studies showing rates greater than 20%.⁹ Specific  studies have frequently shown higher prevalence rates in men. For example, researchers from Brazil, Mexico, and the United States found an overall prevalence of genital HPV infection of 65%, based on studying over 1,000 men from those three countries.¹⁰ The incidence of HPV infection in males is high as well. (Incidence refers to the rate of new infections.) A 2011 study showed that the incidence of HPV infections in a group of 4,299 men from Brazil, Mexico, and the United States was an average of about one new infection per person every two years.¹¹

HPV infection is usually asymptomatic, but it can also have serious consequences. HPV infection is the cause of almost all cases of cervical cancer. In the United States, between 2005 and 2009, there were approximately 12,600 new cases of cervical cancer each year, and 4,000 deaths¹²; worldwide, there are approximately 528,000 new cases of cervical cancer each year, and about 266,000 deaths.¹³ In most people, HPV infections are rapidly cleared, with no lingering effects (about 90% of women eliminate the virus after two years). However, in the remaining 10% of individuals, the virus causes a persistent infection, and these individuals may run a higher risk of developing cervical or other cancers, depending on the site of infection, HPV strain involved, and other factors.¹⁴

Characteristics of Human Papillomavirus

Human papillomavirus is a member of the papillomavirus family. The name of this group comes from the Latin papilla meaning nipple or pustule referring to the shape of the lesions and Greek oma meaning a tumor or swelling. The first papillomavirus (cottontail rabbit papillomavirus) was discovered in 1933.¹⁵Subsequently, scientists have identified hundreds of papillomaviruses in humans and other animals.

Electron micrograph of a negatively stained human papilloma virus (HPV) which occurs in human warts.

Source: National Institutes of Health.

Viruses in this group infect a variety of mammals, birds, and reptiles. For example, in addition to humans, papillomaviruses infect horses, cows, hamsters, turtles, chaffinches, gray parrots, rats, dogs, and fish, and probably most animals with a backbone (vertebrates).¹⁶ Papillomaviruses infect skin cells and cells lining the mucous membranes. These viruses are round and are surrounded by a protein coat (called a capsid). Papillomaviruses lack a membrane-bound envelope and are about 55 nanometers in diameter. This is so small that nearly 2,000 of the viruses, laid end to end, would be about the width of a human hair. Because of their small size, papillomaviruses are only visible with an electron microscope. The genetic material in members of this group is a double-stranded circular molecule of deoxyribonucleic acid (DNA). (DNA is a long chain of four possible subunits or nucleotides: adenine, guanine, cytosine, and thymine. The sequence of the DNA subunits determines the genetic information encoded by a cell or virus.) The HPV genome consists of about 8,000 individual units of genetic information (8,000 nucleotides). (A genome is the entire collection of genetic information for an organism or virus, typically in the form of DNA.) Viruses in this family contain a similar set of genes. One group of HPV genes is labeled E for early. As the name suggests, these genes are generally involved in the initial stage of HPV