ContraPest is a

contraceptive Birth control, also known as contraception, anticonception, and fertility control, is the use of methods or devices to prevent pregnancy. Birth control has been used since ancient times, but effective and safe methods of birth control only be ...

-based

pest control Pest control is the regulation or management of a species defined as a pest (organism), pest; such as any animal, plant or fungus that impacts adversely on human activities or environment. The human response depends on the importance of the da ...

tool that causes

infertility In biology, infertility is the inability of a male and female organism to Sexual reproduction, reproduce. It is usually not the natural state of a healthy organism that has reached sexual maturity, so children who have not undergone puberty, whi ...

brown Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing and painting, brown is usually made by combining the colors Orange (colour), orange and black. In the ...

and black rats. It was originally created to supplement existing rodent control strategies and is formulated as a sweet liquid that appeals to rats. It is developed by the U.S.

biotechnology Biotechnology is a multidisciplinary field that involves the integration of natural sciences and Engineering Science, engineering sciences in order to achieve the application of organisms and parts thereof for products and services. Specialists ...

company

SenesTech SenesTech, Inc. () is an Agriculture, agricultural biotechnology life-sciences company, specializing in Birth control, fertility management as a form of pest control. The company's primary product, ContraPest is designed to make Brown rat, brown ...

. ContraPest does not sterilize rats permanently; therefore, a continuous supply of the product is required to be effective. In field tests, SenesTech claims that using ContraPest led to a reduction in rat populations by approximately 40% over a period of 12 weeks or longer. In August 2016, the

U.S. Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent agency of the United States government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it began operation on De ...

approved ContraPest for commercial use.

Mechanism

The formula was originally developed by Drs. Loretta Mayer and Cheryl Dyer as part of a research program studying

heart disease Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs constitute a class of diseases that includes: coronary artery diseases (e.g. angina pectoris, angina, myocardial infarction, heart attack), heart failure, ...

in post-menopausal women using menopausal mice. The first

active ingredient An active ingredient is any ingredient that provides biologically active or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease or to affect the structure or any function of the body of humans or animals. ...

of ContraPest is 4-vinylcyclohexene diepoxide (VCD), which causes destruction of the

antral follicle An antral or secondary follicle, also known as Graafian follicle and tertiary follicle, is an ovarian follicle during a certain latter stage of folliculogenesis. Definitions differ in where the shift into an antral follicle occurs in the stag ...

during

folliculogenesis :''Although the process is similar in many animals, this article will deal exclusively with human folliculogenesis.'' In biology, folliculogenesis is the maturation of the ovarian follicle, a densely packed shell of somatic cells that contains an ...

in the female ovary. ContraPest also contains triptolide, which has been reported to reduce male rat fertility by reducing

sperm motility Sperm motility describes the ability of sperm to move properly through the female reproductive tract (internal fertilization) or through water ( external fertilization) to reach the egg. Sperm motility can also be thought of as the ''quality'', wh ...

and viability. Studies conducted by SenesTech claim to demonstrate that prolonged consumption of ContraPest led to a significant decrease in rat fertility. Rats exposed to ContraPest for 50 days experienced infertility lasting up to 100 days, with reduced litter sizes in those that could still reproduce. A 2020 short-term laboratory trial with wild-caught adult black rats from Hawai'i indicated that exposure to ContraPest bait resulted in complete reproductive inhibition for at least 15 consecutive days before mating and throughout a 43-day breeding cycle. The effect persisted through a second breeding cycle, with partial suppression evident in a third cycle. However, fertility rebounded by the fourth cycle. It is uncertain whether the contraceptive effect affects males or females, given that the treatment impacts both sexes.

Control group In the design of experiments, hypotheses are applied to experimental units in a treatment group. In comparative experiments, members of a control group receive a standard treatment, a placebo, or no treatment at all. There may be more than one tr ...

reproduction was not 100%, potentially due to factors like adjustment to captivity or incomplete fertility in the source population. ContraPest did not induce permanent infertility, suggesting it is a contraceptive rather than a sterilant. Toxicity studies on ContraPest in other animals have revealed few adverse effects. The active ingredients metabolize quickly, typically within 15 minutes. Thus, if a dog or cat consumed a rat that had recently ingested ContraPest, it might experience temporary infertility as a minor side effect.

Use

The city of

Washington D.C. Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with ...

was utilizing a 5,000 unit, four-year supply of ContraPest to be used in all eight wards of the city in an attempt to combat the increasing rat population in 2020. Local news reported that the district was unsure of the company's early claims of success in rat control. Trials in the

New York City Subway The New York City Subway is a rapid transit system in New York City serving the New York City boroughs, boroughs of Manhattan, Brooklyn, Queens, and the Bronx. It is owned by the government of New York City and leased to the New York City Tr ...

system have suggested ContraPest's efficacy in reducing brown rat populations. In 2024, a

City Council A municipal council is the legislative body of a municipality or local government area. Depending on the location and classification of the municipality it may be known as a city council, town council, town board, community council, borough counc ...

bill in

New York New York most commonly refers to: * New York (state), a state in the northeastern United States * New York City, the most populous city in the United States, located in the state of New York New York may also refer to: Places United Kingdom * ...

proposed deploying contraceptive pellets, including ContraPest, to sterilize both male and female rats in designated areas, aiming to reduce the rat population. On September 26, the city council approved pilot programs to use the contraceptive in an effort to reduce its rodent population. The initiative marked a potential shift in the city's long-standing strategy against its rat infestation and was inspired by the death of Flaco the Owl, which raised concerns about rat poison effects.

References

{{Reflist Reproductive toxins Mammal pest control