Acute Illness Associated with Use of Pest Strips

Dichlorvos-impregnated resin strips (DDVP pest strips) are among the few organophosphate products still available for indoor residential use. The residential uses for most other organophosphate products, including most DDVP products, were canceled because they posed unreasonable risks to children.


DDVP pest strips act by inhibiting acetylcholinesterase activity in the brain and nerves of insect pests and are designed to gradually release DDVP vapor for up to four months. Acute illnesses in humans associated with nonlethal acute exposures usually resolve completely, but recovery is not always rapid.


To assess the frequency of acute illnesses associated with DDVP pest strips, cases from 2000 through June 2013 were sought from the 12 states that participate in the Sentinel Event Notification System for Occupational Risks (SENSOR)–Pesticides Program, the National Pesticide Information Center (NPIC), and Health Canada. A total of 31 acute DDVP pest strip–related illness cases were identified in seven U.S. states and Canada. Twenty-six (84%) of the 31 cases were classified as of low severity, and 24 (77%) of the patients were female. Among the 22 cases for which age was known, the mean age of patients was 48 years. Twenty-four (77%) of the exposures occurred in private residences.


The majority of these illnesses resulted from use of the product in commonly occupied living areas (e.g., kitchens and bedrooms), where people spend four or more hours. Contributing factors other than using strips in occupied areas included excessive application (two cases), placing strips in sealed bags to treat infested items (four), lack of skin protection (e.g., gloves or prompt skin washing) (four), placing strips in closets and pantries (three), cutting and tearing strips into smaller pieces (three), and using a heater and fan to accelerate vapor dissemination from strips (three).


Although 26 of the 31 cases involved mild health effects of short duration, five persons had moderate health effects. The most commonly reported affected body systems and their symptoms were neurologic (68%) (e.g., headache), respiratory (55%) (e.g., dyspnea), and gastrointestinal (42%) (e.g., nausea). Five of the 31 persons had health effects considered moderate, including asthma attack, respiratory distress requiring hospitalization, paresthesias, and incoordination.


Currently in the United States, DDVP pest strips are offered in three different sizes: 16 g, 65 g, and 80g. Label directions differ across sizes, but also can differ across brands of the same size. For example, whereas all labels specify that one 65 g or 80 g strip will treat up to 900–1,200 cubic feet, not all labels advise against using the product in smaller spaces, nor do they all provide a clear warning against excessive application. Moreover, some labels list offices as appropriate places for strip placement even though these are typically occupied for four or more hours per day. Finally, although some strips are approved for bed bug control, the directions for use are substantially different for bed bugs versus other insect infestations, which might confuse some users and lead to improper use.


Preventing DDVP pest strip–related illnesses requires educating the public regarding how to correctly use DDVP pest strips and how to control insect pests using methods with the least possible health and environmental hazards.


See the CDC Report