Preventing Infectious Disease in Sports
Warren B. Howe, MD
Practice Essentials Series Editors:
THE PHYSICIAN AND SPORTSMEDICINE - VOL 31 - NO. 2 - FEBRUARY 2003
In Brief: Preventing infectious disease in sports is fundamental to maintaining team effectiveness and helping individual athletes avoid the adverse effects of illness. Good general hygiene practices, immunization, efforts to minimize exposure to specific diseases, and certain prophylactic measures are essential. Teammates, coaches, athletic trainers, officials, and healthcare providers should actively participate in these preventive efforts, and community public health resources may be involved when appropriate. In addition to treating individual athletes, the team physician's role is to increase awareness, vigilance, and compliance with procedures to prevent the spread of disease.
Dealing with infectious disease in athletes is, perhaps, not as dramatic as attending to a sudden on-field injury, but it can have a much greater effect on the team's success. Military history shows that infectious diseases routinely disable more fighting men than do battle wounds, and the situation is similar in competitive sports. Just imagine yourself, as a team physician, confronting an outbreak of herpes gladiatorum on the wrestling team during the final weeks of the season, or the specter of half your football team suddenly developing vomiting and diarrhea on Saturday morning just before facing the toughest opponent of the year, or six simultaneous cases of influenza on your basketball team in January. Under these circumstances, the importance of infectious disease prevention in sports becomes crystal clear.
Luckily, most situations involving infectious disease in sports are not that sensational, but prevention can play a huge role in athletes' success. Some infectious diseases that may be spread during sports participation can threaten long-term health or even life itself. The principles of infection prevention must be practiced routinely by team members, team physicians, and the entire sports medicine team (see the Patient Adviser, "Avoiding Infections: Staying Healthy, Performing Well").
Sports Participation and Infectious Disease
Athletes and the general population are exposed to similar infections, although some (eg, cutaneous infections seen in close contact sports, such as wrestling) may be sport specific. Before considering specific preventive measures, it is important to understand the interactions between exercise and the incidence and severity of infections. It is also appropriate to consider the effects of infection on athletic performance and the question of whether or not an athlete with an infection should participate.
People engaged in regular, moderate exercise appear to have fewer upper respiratory infections (URIs) compared with sedentary people, but infection incidence increases with severe exertion.1 It has been postulated that severe exercise may produce a period of immunodepression, thus creating an "open window" when the athlete may be more susceptible to infection, but the fitness produced by regular, moderate exercise improves immunity.2-4 However, no definitive proof of the open window theory exists, despite many studies that look at relationships between exercise and multiple parameters of immune function.
Exhaustive exercise seems to increase the severity of some viral illnesses, suggesting that exercise during the prodrome or early acute phase may worsen or prolong the illness or increase the incidence and severity of complications.1 Most of these reports are anecdotal. The relationship between certain virus infections, such as Coxsackie, and the development of myocarditis and viral cardiomyopathy seems well established, and there is some suggestion that the risk increases when heavy exercise occurs during the infection.1,5
Viral infections have been linked to measurable decrements in athletic performance.1,6 Muscles seem especially affected, with reductions in the isometric strength of skeletal muscle, cardiac muscle strength, and respiratory muscle strength. Infection may trigger latent reactive airway disease. Observed sudden decrements in performance may be related to URI or to subclinical viral infections.1
The question of whether or not to exercise during illness is common. Mild exercise during an illness such as the common cold is reasonably safe, but strenuous activity is probably best avoided. Eichner7 recommends that athletes with such illnesses be guided by a "neck check." Symptoms localized above the neck, such as stuffiness or mild sore throat, indicate that the athlete may try a reduced workout and, if symptoms improve during exercise, may increase the intensity. Symptoms below the neck, including fever, muscle aching, significant cough, vomiting, or diarrhea, attest to a more serious illness, and the athlete should rest until symptoms have fully resolved.
Basic Hygiene Practices
Disease transmission can occur by person-to-person contact (eg, cutaneous infections, blood-borne pathogens), airborne droplet spread (eg, viral infections such as colds, influenza, and measles), or by exposures to common sources of infection (eg, fomites, enterovirus infections, food poisoning).8,9 Good general hygiene practices and efforts to minimize exposure to specific diseases form the foundation of preventive efforts.5 These precautions are straightforward, quite simple, and are probably quite familiar. They merit repetition here because their violation, which occurs frequently, is often the major factor in an infectious disease outbreak.
Limiting exposure to ill individuals or potential existing contagion is important. Athletes should minimize contact with persons who are obviously ill. Avoiding crowds, unnecessary travel, and close interaction with young children will reduce exposure. Topical insect repellents are recommended when athletes are in locales where insect-borne disease is a risk.
Frequent hand washing is one of the most helpful practices, and one of the most neglected. The hands should be thoroughly soaped and thoroughly rinsed, not just briefly swished under running water. Learning to control the unconscious tendency to put one's hands—which are often vectors of contagion—to the mouth, nose, or eyes is helpful.
Showering with a good-quality soap after every practice or competition is important, and I also recommend that athletes who are engaged in sports involving close skin contact shower before activity as well. Coaches, especially those who engage in contact with their athletes during practice, as is often the case in wrestling, should follow the same pre- and postactivity shower rules. Showers should be frequently sanitized, and users should wear shower clogs or similar footwear.
Protecting the skin from breaches where infection may enter is an important step. Keeping feet and intertriginous areas dry prevents skin maceration. Frequent changes of absorbent socks, adequate drying of shoes between uses, and use of foot powder is helpful. The use of a handheld hair dryer to dry the groin, genital, intragluteal, and intercrural regions after bathing looks silly, but is very effective at reducing residual moisture in those areas. Minor abrasions and superficial wounds should be cared for with soap-and-water cleansing, perhaps using topical antibacterial lubricant preparations, and bandaging as necessary, to prevent secondary infection.
Safeguarding water sources, such as water bottles, drinking hoses, ice buckets, and ice machines, to avoid contamination is essential. Individual, name-labeled water bottles that are sanitized daily and used only by their owner are best, but, for large teams in hot weather, they may be insufficient for drinking water demands. In those cases, drinking fountains designed so that water does not drop from a drinker's mouth back to the water source are acceptable. Access to ice chests must be restricted to designated personnel, scoops used to remove ice must be frequently sanitized, and hand contact with the ice must be avoided. Soda cans and sports drink bottles should not be shared. Athletes should be aware of the potential for infection, such as leptospirosis, following inadvertent ingestion of water from lakes, ponds, or rivers in which competition is held.
Wearing clothing and equipment that is clean, in good repair, and appropriate for the activity is helpful. Clothing, personal equipment, and towels should not be shared between individuals. Practice clothing should be laundered and dried daily, and equipment that directly touches skin, such as wrestling headgear, must be sanitized daily.
Cleaning practice surfaces, such as mats, with an appropriate germicide prior to and following each practice session is recommended. Most proprietary cleansing solutions or dilute bleach (1 part bleach in 9 parts water) are highly effective. The equipment manufacturer can confirm compatibility of the cleanser with the surface to be cleaned. Street shoes must not be used on performance surfaces, and, ideally, only footwear restricted to use on the designated surface should be allowed.
Avoiding every potential source of infection is not possible, so supporting the body's immune system by using some commonsense measures and immunization, when available, is also recommended.
Fatigue and overtraining have been implicated as risk factors for infection. Adequate and regularly scheduled sleep and rest periods should be the rule for athletes. Workouts should be spaced with adequate recovery time, and activity should be varied to avoid the stress that arises from boredom. Life stresses should be minimized for the athlete when possible, but this goal is often difficult to achieve.
Improper nutrition may be a risk factor for infectious disease; therefore, a well-balanced diet is recommended. Recent studies suggest that excessive limitation of fats or calories may predispose athletes to infection, and fat content up to about 40% of total calories has been suggested to maintain optimal immune status.10 Theoretically, maintaining a high carbohydrate intake should diminish physiologic stress by several mechanisms, thereby improving host resistance to infection,5 but such an effect has not yet been demonstrated by controlled study. Rapid weight loss or repeated weight fluctuations, such as those experienced by wrestlers who employ severe prematch dehydration, should be avoided. Vitamin C ingestion has been found to reduce postevent URI incidence in ultramarathoners, but the studies have not been replicable, and long-term effectiveness of vitamin supplementation has not been determined.3
Food-borne illnesses, such as viral gastroenteritis, bacterial food poisoning, or travelers' diarrhea, can disrupt even the best nutritional program. Food obtained from reliable sources, that has been properly prepared and served piping hot or kept carefully refrigerated, as appropriate, is essential. Careful hand washing before meals and snacks and using only clean utensils will minimize risk.11,12
Immunization is a critical component of prevention.13 My recommendations for athletes are summarized in table 1. Influenza vaccine for athletes who compete during the flu season (usually October through March in the United States) is certainly approaching designation as "essential." The vaccine is quite effective in limiting spread, mitigating symptoms if infection should occur, and thereby avoiding the serious disruption in practice and competition that can result if an influenza epidemic affects a team.1
Supply problems with certain vaccines have occurred in recent years. Diphtheria-tetanus toxoid and influenza vaccines are current examples, although availability is improving. If vaccines are in short supply, athletes must be fit into whatever prioritization schedule is announced by public health authorities.
For an unimmunized team exposed to influenza, use of antiviral agents such as amantidine hydrochloride, rimantadine hydrochloride, or oseltamivir phosphate may be effective in preventing or mitigating further cases during the 2 weeks necessary for immunization to produce adequate protection.6 These medications may have undesirable effects on performance, such as fatigue, dizziness, confusion, headache, nausea, or vomiting.
Body Fluid and Skin Basics
The routine application of universal precautions when dealing with blood and body fluids is mandatory to minimize the spread of blood-borne pathogens. Some systemic infections may prompt temporary exclusion of the athlete from play, and certain skin infections demand special care to decrease the risk of contagion.
Body fluids. Universal precautions (table 2) should be followed routinely, and all body fluid contact should be considered infectious. The risk of transmission of the human immunodeficiency virus (HIV) and other blood-borne pathogens during athletic activity is very low, probably negligible.14 No definitive cases of HIV transmission in sports have been reported, and only one case of hepatitis B appears to have been transmitted during a game. The risk of blood-borne pathogen transmission through sexual activity, injectable drug abuse, or the abuse of injectable anabolic steroids off the playing field poses a much greater threat to athletes than any risk that may be present on the field.9 The presence of HIV or hepatitis B infection in an athlete is not an indication for prohibiting contact sports participation. Withhold-from-play decisions should hinge on the same medical criteria that are applied to noninfected athletes.15
Athletes with acute symptoms of systemic infectious disease, such as severe respiratory infection, active gastroenteritis with vomiting or diarrhea, or exanthems, should be held from practice or contact until the symptoms have abated. Antibiotics are, in general, appropriate only for treatment of specific infections. However, prophylactic antibiotics, such as a quinolone (currently preferred) or trimethoprim plus sulfamethoxazole, are sometimes recommended for athletes who may be at high risk for disruption of practice or competition schedules because of traveler's diarrhea.11
Skin lesions. Infectious skin diseases must be recognized promptly, and steps must be taken to isolate affected athletes from contact with others that might result in spreading contagion. Potentially infectious skin diseases include herpes simplex, fungal infections, and bacterial infections, such as impetigo. Teammates, coaches, officials, and team physicians must take an active role in maintaining surveillance for infections. Any athlete with open, weeping, pustular, or vesicular lesions on the skin must be kept from practice and competition until an accurate diagnosis has been made, appropriate treatment has been employed for sufficient time, and adequate resolution of the lesions is apparent.
Although it is tempting to believe that carefully bandaging an athlete's infectious lesion will prevent spread to teammates or opponents, experience testifies to the futility of this practice. Bandages become wet, shift position during activity, or peel off sweaty skin. Wrestling rules specifically prohibit participation while bandages cover potentially contagious lesions, and this rule should be a model for all contact sports.
Suppressive or prophylactic medication is sometimes indicated to control or prevent skin infection. Because herpes simplex lesions can recur with little warning and viral shedding may occur even in the absence of lesions, season-long suppression with oral antiviral agents (eg, acyclovir, 800 mg daily; famciclovir, 125 mg twice a day; or valacyclovir hydrochloride, 500 mg daily) has been proposed for athletes in close-contact sports, such as wrestling.6 Such use is, of course, not an approved indication. The use of antifungal drugs such as itraconazole and fluconazole as prophylaxis for tinea gladiatorum has been proposed, although the issues of cost, possible adverse drug effects, and the potential for development of drug-resistant fungi must be weighed.16
Commercial skin protectants and cleansers designed to prevent skin infections are available and are mostly targeted toward wrestlers. Although many anecdotal and testimonial reports of efficacy are used in marketing, objective evidence that such agents are more effective than scrupulous basic hygiene measures previously discussed is not available.
Every community has public health agencies whose responsibility, among others, is to combat the spread of infectious disease. These agencies can be valuable allies in preventive efforts, because they may provide access to laboratory and epidemiologic resources that can help track down the source of an obscure infection. They can also suggest treatment and control measures to minimize disease outbreaks. Local health departments have ready access to state and federal assets that can be employed to assist in diagnostic, epidemiologic, and containment efforts.
The key to effectively using public health resources is to understand the requirements for reporting infectious disease in your locality and to make reports early when contagion is suspected. The local health officer should be viewed as a valuable consultant, even if he or she is not experienced in sports medicine. Combining expertise for prevention and during disease outbreaks is sure to improve outcomes.
The entire sports medicine team must be involved in preventing infection. Educational efforts directed at coaches, athletic trainers, sports officials, school administrators, and the athletes themselves will improve understanding, and create "deputies" who will extend the effect of the concerned physician into day-to-day activity. By recruiting all involved persons in the effort required for prevention, the risk of infectious disease disrupting an athlete's performance or a team's season will be minimized, to everyone's benefit.
Dr Howe is the team physician at Western Washington University in Bellingham, Washington. Address correspondence to Warren B. Howe, MD, 4222 Northridge Way, Bellingham, WA 98226; e-mail to [email protected].
Disclosure information: Dr Howe discloses no significant relationship with any manufacturer of any commercial product mentioned in this article. Oral antiviral agents are mentioned in this article for an unlabeled use.