Hobo spider

The hobo spider is a relatively large spider, of caramel or brown color with a characteristic “herring bone” pattern on its abdomen and distinct stripes on either side of the cephalothorax (Figure 1). It has been found in northern Utah as far south as Sanpete County and as far east as Summit County (Figure 2). While the common European name for the hobo spider is the aggressive house spider, the spider is no more aggressive than other wandering spiders.

In the fall, female spiders build webs and remain stationary. Male spiders begin nocturnal wandering in search of mates. Spiders may enter houses, often in large numbers, from outside habitats during this period, and most bites occur in the fall. However, hobo spiders do not usually lay their eggs inside homes. Hobo spiders are not good climbers and are usually found at ground or basement levels. Spiders can be controlled from entering the house by ensuring a tight seal between the foundation and the wood structures of a house, and in all low portals of entry such as under outside doors. Ground vents and basement windows should be properly sealed or screened. In addition, good house cleaning practices will discourage the spiders from inhabiting areas where people are present.

A large percentage of hobo spider bites are dry defensive bites where no venom is injected. When envenomation does occur, both local and/or systemic manifestations may appear. Typically, immediately following envenomation, a large area of erythema (redness) forms around the bite site. This erythema will usually disappear in a few hours, leaving a small reddish induration (hardened area). Within 24 to 48 hours, blistering may occur at the site. These blisters may rupture, leaving an open ulceration, which will progress to an escar (scab). By about three weeks post-bite, this becomes pronounced, giving the lesion a “target and bulls-eye” appearance. Eventually, the eschar is sloughed and the lesion gradually heals, leaving a scar. In some instances, particularly when the bite is delivered in an area of fatty tissue, the lesion may become deep and extensive and may not heal for two to three years. In most instances, however, the lesion heals in about 45 days after the original bite.

The yellow sac spider is a relatively small spider (10 mm body length) with a light yellow or yellow-green color and no distinguishing marks on the abdomen, cephalothorax or legs. These spiders are common throughout Utah, found in homes year-round, and may spin a web in ceiling corners. These spiders are best controlled by regular removal of the webs and nests.

Bites from yellow sac spiders are not as severe as those from hobo spiders. These bites generally produce instant, intense stinging pain, followed by localized redness, swelling and itching. The bite may or may not become a necrotic lesion, but if that occurs, healing is usually complete within eight weeks. Systemic effects are usually not severe and include chills, fever, headache, dizziness, nausea, anorexia. Shock is a rare complication.

A principle task of the Bureau of Epidemiology (BOE) is to conduct surveillance. The BOE is continually working to improve its surveillance capabilities. Recent awards from the Centers for Disease Control and Prevention (CDC), will assist the BOE with this undertaking.

Assessment of the Blood Lead Levels in Utah Medicaid Children

Since 1990, the BOE has maintained a registry of blood lead testing results on Utah residents. Initially, the registry only recorded the results of adults with elevated blood lead levels, as part of the Adult Blood Lead Epidemiology and Surveillance (ABLES) project. In 1996, the BOE expanded the Utah Blood Lead Registry (UBLR) to include children and started the Child Blood Lead Epidemiology and Surveillance (CBLES) project. The CBLES project investigates child blood lead poisoning, and ensures that children with elevated blood lead levels receive appropriate medical intervention and follow-up.

Nationally, Medicaid children have been identified as a particularly high risk group for blood lead poisoning. Medicaid children are at risk because 1) they often live in high risk housing - older homes that contain lead-based paint and are in poor condition, and 2) they live in homes where working adults are more likely to work in high risk occupations such as auto repair or scrap metal work. (Additionally, these adults are less likely to have received the appropriate training for protecting their families from carry home lead.)

To assess the risk of Utah Medicaid children for blood lead poisoning, the BOE will conduct a targeted surveillance project. Bureau staff will perform blood lead testing in a sample of Utah’s Medicaid child population using two portable blood lead analyzers to be purchased with funding from the CDC. While these surveillance teams are testing Medicaid children for blood lead, the teams will also conduct health risk assessments, and in some cases, limited environmental investigations.

ATSDR Cooperative Agreement to Conduct Site-Specific Health Assessment Activities

In September 1998, the BOE’s, Environmental Epidemiology Program was awarded funding for a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). The funds will be used to build the BOE’s capacity to conduct site-specific environmental health assessment activities in Utah. With this new capacity, the BOE will be better able to conduct environmental health assessments for sites that are contaminated with chemical toxins such as industrial wastes or mining wastes. The objectives of the project are to collect information about the contaminants from data provided by other state and federal agencies, identify populations at risk, identify possible exposure pathways, determine if the contaminants pose a health risk, and determine if any mitigating actions are needed. Another objective is to develop the capacity to provide community education about the investigated sites. This objective involves assessing the concerns of the community and providing information to address those concerns and additional concerns that may be raised by the health assessment.

The BOE is conducting assessments on a variety of sites. These sites include those that are listed in the National Priorities List (NPL) under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund), and other industrial sites that have produced or are producing toxic waste.

Epidemiology and Laboratory Capacity for Infectious Diseases Cooperative Agreement

In 1998, the BOE’s, Communicable Disease Control Program and the Utah Public Health Laboratory were awarded funding for a cooperative agreement with the CDC to increase the capacity for conducting infectious disease surveillance and providing a rapid public health response. The cooperative agreement will assist the BOE in accomplishing the following goals:

The Communicable Disease Control Program is currently assisting local health departments in acquiring the capability to submit data to the BOE electronically. Eight of the twelve local health districts are now able to submit communicable disease data to the Bureau electronically. The Communicable Disease Control Program is developing an Internet-based electronic reporting system to allow clinical laboratories, healthcare providers, and hospital emergency departments to report directly to the Bureau.

The BOE, with other state and local agencies, has recently received notification of an award of funds that will be used to develop an effective public health response to bioterrorism. Funds will be used to support planning activities, assessments, surveillance, epidemiological investigations, and training. In addition, funds will be used to improve the state laboratory’s capacity to identify potential bioterrorism agents, and to develop a statewide comprenhensive health alert network.

Utah is growing, both in population and in national and international influence. The state has some of the nation’s most popular winter and summer vacation sites. Utah is home to a variety of military establishments and other important industries. These scenarios are unlikely to change in the future, particularly as Utah prepares to host the 2002 Winter Olympics. With this CDC funding, the BOE will be able to increase its capacity for conducting surveillance for and responding to all diseases including those potentially associated with bioterrorism.

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The Epidemiology Newsletter is published monthly by the Utah Department of Health, Division of Epidemiology and Laboratory Services, Bureau of Epidemiology, to disseminate epidemiologic information to the health care professional and the general public.

Rod Betit, Executive Director, Utah Department of Health
Charles Brokopp, Dr.P.H., Division of Epidemiology and Laboratory Services
Craig R Nichols, MPA, Editor, State Epidemiologist, Director Bureau of Epidemiology
Gerrie Dowdle, MSPH, Managing Editor
Connie Dean, Production Assistant

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