Animal-bites: a major public health problem

Animal-bites pose a major public health problem in children and adults worldwide. The health impacts of animal-bites are dependent on the type and health of the animal species, the size and health of the bitten person, and accessibility to appropriate health care.

Numerous animal species have the potential to bite humans; however the most important are those arising from snakes, dogs, cats and monkeys.
Snake-bites
Scope of the problem

Worldwide, up to five million people are bitten by snakes every year. Of these, poisonous (envenoming) snakes cause considerable morbidity and mortality. There are an estimated 2.4 million envenomations (poisonings from snake-bites) and 94 000–125 000 deaths annually, with an additional 400 000 amputations and other severe health consequences, such as infection, tetanus, scarring, contractures, and psychological sequelae. Poor access to health care and scarcity of antivenom increases the severity of the injuries and their outcomes.
Who is most at risk?

The majority of snake-bites occur in Africa and South-East Asia. Snake-bites are most common among people living in rural, resource-poor settings, who subsist on low-cost, non-mechanical farming and other field occupations. Agricultural workers, women and children are the groups most frequently bitten by snakes. Adding to the burden of these injuries is their socioeconomic impact on families and communities. Adult victims are often the wage earners or care providers of the family unit; and child victims can suffer lifelong disability intensifying demands on families and communities
Treatment

Approximately 600 species of snake are venomous and approximately 50-70% of bites by these cause envenomation. At the time of a bite, the cornerstone of care is complete immobilization of the affected body part and prompt transfer to a medical facility. Tourniquets and cutting wounds can worsen the effects of the venom and should not be used as first aid. Frequently, victims of snake-bites will require treatment with antivenom. It is important that the antivenom is appropriate for snakes endemic to the region. Additional measures include wound cleansing to decrease infection risk, supportive therapy such as airway support, and administration of tetanus vaccine upon discharge if the person has been inadequately vaccinated against tetanus.
Prevention of snake-bites and their serious health consequences

Prevention of snake-bites involves informing communities about snake-bite risks and prevention techniques, such as to:

avoid tall grassy areas;
wear protective shoes/boots;
keep storage areas clear of rodents;
remove rubbish, woodpiles and low brush from around the home;
store food in rodent-proof containers, raise beds above floor level and tuck mosquito nets securely under sleeping mats within the home.To prevent or limit the serious health consequences of snake-bites, health-care providers should be educated on snake-bite management, including the proper use and administration of antivenom. Public health authorities and policy-makers should ensure appropriate supplies of safe and effective antivenoms to communities, countries and regions where they are most needed, and prioritize research initiatives that will further determine the burden of these injuries.
Dog-bites
Scope of the problem

There are no global estimates of dog-bite incidence, however studies suggest that dog-bites account for tens of millions of injuries annually. In the United States of America for example, approximately 4.5 million people are bitten by dogs every year. Of these, nearly 885 000 seek medical care; 30 000 have reconstructive procedures; 3–18% develop infections and between 10 and 20 fatalities occur. Other high-income countries such as Australia, Canada and France have comparable incidence and fatality rates.

Low- and middle-income country data are more fragmented, however some studies reveal that dogs account for 76–94% of animal-bite injuries. Dog-bite fatality rates are higher in low- and middle-income countries than in high-income countries as rabies is a problem in many of these countries, and there may be a lack of post-exposure treatment and appropriate access to health care. An estimated 55 000 people die annually from rabies, and bites from rabid dogs account for the vast majority of these deaths.
Who is most at risk?

Children make up the largest percentage of people bitten by dogs, with the highest incidence in mid-to-late childhood. The risk of injury to the head and neck is greater in children than in adults, adding to increased severity, necessity for medical treatment and death rates.

In some countries, males have a higher frequency of dog-bites than females. Dog-bites account for over 50% of animal-related injuries in people who are travelling.
Treatment

Treatment depends on the location of the bite, the overall health condition of the bitten person and whether or not the dog is vaccinated against rabies. The main principles of care include:

early medical management;
irrigation and cleansing of the wound;
primary closure if the wound is low-risk for developing infection;
prophylactic antibiotics for high-risk wounds or people with immune deficiency;
rabies post-exposure treatment depending on the dog vaccination status;
administration of tetanus vaccine if the person has not been adequately vaccinated.

Prevention of dog-bites and their serious health consequences

Communities – especially children – should be informed about the risks of dog-bites and prevention techniques such as avoiding stray dogs and never leaving a child unattended around any dog.

Health-care providers should be educated on the appropriate management of dog-bites. Health authorities and policy-makers should ensure rabies control within dog populations, ensure appropriate supplies of rabies vaccines for potential rabies exposure in people, and develop data collection systems to further document the burden of this problem.
Cat-bites
Scope of the problem

Worldwide, cat-bites account for 2–50% of injuries related to animal-bites. They are commonly second to dog-bites in terms of incidence. In Italy for example, the incidence of cat-related injuries is 18 per 100 000 population, while in the United States of America, there are an estimated 400 000 cat-bites and 66 000 visits to hospital emergency departments every year.
Who is most at risk?

Female adults have the highest rate of cat-bites.
Treatment

Treatment depends on the location of the bite and the rabies vaccination status of animal species inflicting the bite. The main principles of care include:

early medical management including wound cleansing;
prophylactic antibiotics to decrease infection risk;
rabies post-exposure treatment depending on the animal vaccination status;
administration of tetanus vaccine if the person has not been adequately vaccinated.

Prevention of cat-bites and their serious health consequences

Communities should be informed about the risks of cat-bites and prevention techniques for cat-bites including vaccinating cats against rabies.

Health-care providers should be educated on the appropriate management of these injuries. Health authorities and policy-makers should ensure rabies control within animal populations, and appropriate supplies of post-exposure rabies treatment and antibiotic prophylaxis for bitten people. They should also support research initiatives directed at providing more information on the burden of cat-bites.
Monkey-bites
Scope of the problem

Monkey-bites account for 2–21% of animal-bite injuries. In India for example, two studies found monkeys to be second to dogs as the most common source of animal-bite injuries.
Who is most at risk?

Monkey-bites are an important risk among travellers, being the second most common animal-bite risk to travellers after dog-bites.
Treatment

Treatment depends on the health status of the patient, the location of the bite and whether or not there is a suspicion of rabies in the monkey. The main principles of care include:

early medical management including wound cleansing;
prophylactic antibiotics to decrease infection risk;
rabies post-exposure treatment depending on the animal vaccination status;
administration of tetanus vaccine if the person has not been adequately vaccinated.

Prevention of monkey-bites and their serious health consequences

Communities and travellers should be informed about risks of monkey-bites and prevention techniques.

Health-care providers should be educated on the appropriate management of these injuries. Health authorities and policy-makers should ensure rabies control within monkey populations, and appropriate supplies of post-exposure rabies treatment and antibiotic prophylaxis for bitten people. They should also support research initiatives directed at providing more information on the burden of monkey-bites.
WHO response

WHO is working to address the public health problem of animal-bite injuries.

For snake-bites, WHO has launched several tools to help guide the appropriate development, distribution and administration of antivenom.

For rabies, WHO advocates greater access to post-exposure treatment through promoting increased production of rabies biologicals, continuing education in rabies prevention and control, and widespread immunization of dog populations.

For all animal-bite injuries, WHO:

prioritizes data collection initiatives to help determine the burden and risk factors of these injuries;
advocates the strengthening of emergency response services for people that are injured;
promotes research initiatives that focus on effective prevention interventions and populations most affected.

Source: WHO Release News