Public Health Entomology

Jerome Goddard

• Publisher: CRC Press
• Year: 2022
• ISBN:
  9781000543049
• Edition: 2
• Topic: Biological Sciences
• Subtopic: Entomology
• Index: Biological Sciences

In the struggle against vector-borne diseases, it is critical that we bridge the gap among vector control workers on the ground (practitioners), public health planners and administrators, and (academic) medical entomologists. This second edition of Public Health Entomology is designed to fit certificate courses in public health entomology offered by universities and U.S. Centers of Excellence. It comprehensively examines vector-borne disease prevention, surveillance, and control from a governmental and public health perspective with worldwide application.

Divided into two sections, the book begins with a historical account of the early beginnings of pest control and public health. Next, it outlines the concepts, design, and implementation of a sound public health entomology program, including issues associated with pesticide use, FEMA and other disaster response entities, and an adverse, chemophobic public. The second section provides an overview of some of the most common public health pests that are found globally. Copious photos and line drawings accentuate the text, along with text boxes and sidebars. The new edition addresses "IPM and Alternative Control Methods" in each section, expands the Lyme disease section, and includes other new and emerging tick-borne diseases (TBD). It providesenhanced discussion of working with local political figures and jurisdictions, as well as partnerships with academia, and is generally more worldwide in scope.

Author Jerome Goddard designed and implemented the vector control program along the Mississippi Gulf Coast after Hurricane Katrina. His ability to communicate his knowledge and experience to public health students, professionals, and the general public make this book an essential resource for preventing disease from these vector-borne threats.

section one Essentials of Public Health and Entomology

chapter one History of Medical Entomology and Public Health

Introduction and Background

“The more things change, the more they stay the same” is an appropriate quote for public health entomology in the 21st century. If one reads some of the oldest works on medical entomology and preventive medicine, for example, Griscom’s speech before the New York Academy of Sciences (1855),¹ the Bulletin of the Sanitary Commission (1863),² Doan’s Insects and Disease (1910),³ and Pierce’s Sanitary Entomology (1921),⁴ the themes are exactly the same as those found in entomological, medical, and public health literature today:

1. Entomology bears a two-fold relationship with human health: helping provide adequate food supply and preventing disease transmission.
2. Disease agents can be transferred to humans by several methods, including direct contact, food, insects, soil, and fomites.
3. Both mechanical and biological transmission of disease agents by arthropods are important, as well as efforts to block them.
4. All attempts to link arthropod transmission or causation of disease need to be rigorous and well thought out.
5. Basic sanitation measures such as clean water, sewage disposal, and use of screen wire for windows and doors are absolutely critical in preventing vector-borne disease. In fact, sanitation is the superior activity in disease control, even above quarantine.⁵

Even in the midst of modern technology, such as complicated molecular tools for identifying vector-borne diseases and their agents, these above-mentioned themes should be overarching guides to our research, education, and disease prevention efforts. Public health is often a matter of doing the same thing over and over—hammering home certain unalterable facts about health, disease prevention, and ways to remain healthy. Further, the short nearly 150-year-old era of modern medical entomology has taught us to be prepared, to be ready, for disease outbreaks (both old and new ones) resulting from disasters and wars (for a good discussion of medical entomology during wartime, see Cushing).⁶

Medical Entomology versus Public Health Entomology

Medical entomology is the scientific discipline of the study of insects, but often includes other arthropods, which may directly or indirectly affect human health. Negative effects from arthropods may range from blisters, bites, and stings, to disease transmission and allergic reactions. Medical entomology is largely an academic discipline housed in university entomology or biological sciences departments.

Applied aspects of medical entomology may be seen in military units, focused on protecting military personnel from arthropod-borne diseases, or federal, state, or local governmental agencies such as state health departments or the U.S. Centers for Disease Control and Prevention. This is where medical entomology becomes public health entomology—applied entomology pertaining to human health, safety, and well-being.

Public health entomology is concerned with not only the arthropods themselves, but also the prevention, surveillance, and control of vector-borne diseases. More importantly, protection against pests and vector-borne diseases includes an enforcement or regulatory function, which sets public health entomology apart from traditional medical entomology. Reviewing the history of medical entomology reveals the distinctions between academic and applied entomology and the importance of applied entomology to the field of public health.

Historical Aspects of Medical Entomology

Long before anyone knew about the causative agents of medical conditions, it was recognized that insects might produce diseases.⁴ About 2500 bc, a Sumerian doctor inscribed on a clay tablet a prescription for the use of sulfur in the treatment of itch, a chemical we now know kills itch and chigger mites.⁶ Other recorded instances of arthropod-borne diseases and infestations can be found in the Old Testament, beginning with accounts of plagues on the Egyptians. For example, the third plague, called “lice” in the King James version of the Bible (in later translations more accurately termed “gnats”), was likely Culicoides midges, which transmitted the causative agents of African horse sickness and bluetongue to Egyptian livestock (which was, by the way, the fifth plague).⁷ The sixth plague consisted of boils and ulcers on humans and animals, which could have been the disease called Glanders, transmitted by biting flies.⁷ More recent evidence of health issues from arthropods has been found as well. First-century bc hair combs containing remains of lice and their eggs have been unearthed in the Middle East.⁸ Peruvian pottery from about 600 ad shows natives examining their feet—and their feet display what appear to be holes where chigoe fleas (burrowing fleas) had been removed.^9,10 Other pottery found near the Mimbres River, New Mexico, dated to 1200 ad, clearly depicts a swarm of mosquitoes poised for attack. For hundreds of years after that, there were hints and suggestions made by various people who imagined a connection between insects and diseases. For example, in 1853, Dr. Louis Beauperthuy, a French physician, elaborately argued that yellow fever is transmitted to humans by mosquitoes (but he thought it was by mechanical transmission from decomposing matter which they had visited).¹¹ But these suggestions were almost completely ignored by the medical community. In 1871, the idea that any specific disease might be insect-borne was not even mentioned in any of the standard medical literature.¹¹

That started to change in the late 1800s, when several fundamental discoveries were made over a 20-year period linking arthropods with the causal agents of disease.¹¹ In 1878, Patrick Manson observed development of the nematode Wuchereria bancrofti in the body of the mosquito Culex quinquefasciatus, and eventually he and others proved that mosquitoes were indeed the vector of these filarial worms. Charles Laveran, in 1880, found that a protozoan may be the causative agent of human malaria, and 9 years later, Theobald Smith discovered the protozoan Babesia bigemina, causative agent of Texas cattle fever. In 1893, Smith and F.L. Kilbourne proved that the cattle tick Boophilus annulatus is the vector of Texas cattle fever. Two years later, David Bruce investigated the animal disease nagana and found that its vector is the tsetse fly. In 1897, Ronald Ross linked malaria parasites¹² to certain mosquitoes, which he and others later identified as Anopheles. Walter Reed and his colleagues first reported an association between mosquitoes and yellow fever,^13,14 while a few years later, Carlos Finlay and other members of the Yellow Fever Commission definitively proved that yellow fever is carried by the mosquito Aedes aegypti. In 1902, David Bruce discovered the causative agent and vector of African sleeping sickness (trypanosomiasis), and in 1909, Nicolle established that the body louse is the vector of Rickettsia prowazekii, the agent of epidemic typhus.¹⁵ Although these are the primary (early) discoveries in medical entomology, the list goes on of modern major advancements concerning arthropods and the role they play in disease transmission.

Arthropods themselves, as well as diseases they transmit, have greatly influenced human civilization. Sometimes the influence has been notable or recorded, such as when plague epidemics swept through the Middle East or Europe, louse-borne typhus decimated armies, or yellow fever destroyed entire armies or cities. There is an account of plague in Egypt circa 1200 ad, stating that more than a million people died.¹⁶ The famous French emperor Napoleon Bonaparte crossed the Niemen River into Russia in June 1812 with 420,000 men, but within 6 months, he only had 3,400 men left, most having died from epidemic typhus.¹⁶ Typhus also ravaged Russia from 1918 through 1922, leading to approximately 30 million deaths in the civilian population.¹⁷ Yellow fever has been just as devastating. During the Haitian–French War (1801–1803), Napoleon’s largest expeditionary force of approximately 50,000 soldiers was almos...