Presentation on theme: "Cockroaches And Disease. Basics Order: Blattaria 4000 species worldwide 57 species in the U.S. 18 species have become serious domestic pests The most."— Presentation transcript:
Cockroaches And Disease
Basics Order: Blattaria 4000 species worldwide 57 species in the U.S. 18 species have become serious domestic pests The most important medically are: –Blattella germanica (German cockroach) –Blatta orientalis (Oriental cockroach) –Periplanta americana (American cockroach) –Supella longipalpa (Brown-banded cockroach)
Biology Like warmth (climate plays a role) –Cold Climates –Warm Climates Nocturnal Omnivorous Live for 5-10 weeks without water Live many months without food –Not a limiting factor –Nymphs often die 7-10 days
Life Cycle Hemimetabolous Eggs are laid encased in a capsule called an ootheca –Typically 18-40 –Deposited or cemented to surfaces –4-90 ootheca Nymphs –Hatch after 1-3 months –Wingless –Number of nymphal stages and length varies with species. Adults –2 year lifespan or more
“Medical” Importance (1) Get into our food supplies (2) Odor (Some stink!) (3) They feed on humans (4) Allergies (5)Transmit pathogens? We tend to call cockroaches insects of sanitary importance. Synanthropic species
American Cockroach Periplaneta americana Originally from Africa. Like damp environments. Sewers, around pipes, ships. Basement or first floor in buildings. Nymphal stage 10-14 months long.
German Cockroach Blattella germanica Most common species in WY. Originally from Africa. Smaller than American. Basement and first floors in buildings. Carries egg capsule. Nymphal stage 2-3 months long.
Oriental Cockroach Blatta orientalis Shiny black, common in WY. Found in sewers, likes basement. More tolerant of cooler temps. Males have short wings, females are long. Nymphal stage 12- 15 months long.
Brown-Banded Cockroach Supella longipalpa Originally from Cuba. 2 broad bands across dorsum. All rooms in house. Likes high places versus low. Big problem in the Southern U.S. Glue eggs to things. Often ships in with Furniture.
Control Be clean! Insecticidal spraying –E.g. malathion, carbamates Pyrethroids –E.g. permethrin Boric Acid Powder (borax) –Contact insecticide and stomach poison. Organophosphates and Carbamate Insecticides –1-2% added to baits of food Insect Growth Regulators (IGRs) –E.g fenoxycarb, hydrophen, methoprene. Pheromones and sticky traps
TRUE BUGS Bed bugs and Triatomine bugs
Basics Order: Hemiptera 80,000 known species most in tropics. Worldwide distribution The most sucessful of the Hemimetabolic insects. Divided into two groups the Heteroptera and the Homoptera.
Family Cimicidae (Bed bugs, poultry bugs, bat bugs) 20 different genera Name given for host they feed on. Nocturnal. Host specific, but will cross over it no natural host is available. Three main species: –Oeciacus spp. (swallow bugs) –Cimex hemipterus (Tropical Bed Bug) –Cimex lectularius (Bed Bug)
Life Cycle Egg Nymph (5 instars) Adult Both sexes take blood meals. Can live up to one year without meal. Visit host only for bloodmeal then leave. Females lay 2-3 eggs a day (150-200 in lifetime). Adults can live up to 4 years.
Medical Importance Hep. B Virus and other pathogens. No evidence can transmit to humans. Not considered vectors! Reaction to bites can be severe. Annoyance may cause sleepless nights. Anemia in infants.
Diagnosis Can detect by presence of live bugs, nymphal skins, hatched and unhatched eggs. Small dark brown or black marks may be visible on bed sheets or mattress. No wings, do not spread far. Usually, introduced with furniture and bedding.
Control Insect repellents Pyrethroid-impregnated bed-nets. Spray floors, walls, furniture with 5% DDT emulsion (Tropical countries) Malathion, diazinon, carbaryl, pyrethrins. Mattresses and wooden slates across beds can be sprayed or dusted with insecticides. Fumigate.
Family Reduviidae (Assassin bugs, Kissing bugs) Sub-family: Triatominae More than 130 species in 16 genera. Evolved into a blood feeder that feeds on a wide variety of hosts. Why called kissing bug?
Chagus Disease Host: Variety of vertebrates. Vector: Triatoma spp. –Triatoma infestans –Triatoma dimidiata –Triatoma brasiliensis –Rhodnius prolixus –Panstrongylus megistus Etiologic Agent: Trypanosoma cruzi (protozoan) Reservoir: Wild animals (opossums, armadillos, rodents, monkeys, etc). Chagus disease is a zoonosis, a parasite of wild animals.
Distribution Most Triatoma occur in the Americas. From the Great Lakes of the U.S. to Southern Argentina. 13 species are found in the Old World tropics. All medically important species are confined to the Southern U.S., Central and South America.
Life Cycle of the Vector Hemimetabolous Egg Nymph Adult (6-10 months Eggs –Deposited in or near the habitation of host. Nymph –Hatch after 10-15 days –Stay hidden for 2-3 days –5 instars (each requires 1 blood-meal) –Can ingest 6-12 times their weight in blood. –wingless Adult –1-2 eggs laid each day; 200-300 over lifetime –Ingest 300-400 mg of blood every 4-9 days! –Nocturnal, feeding lasts 10-25 minutes.
Transmission People can become infected with Chagas by unknowingly touching their eyes, mouth, or open cuts after having come into contact with infective triatome bug feces bugs directly depositing infected feces in their eyes eating uncooked food contaminated with triatome bug feces receiving infection from mother during pregnancy or at birth receiving an infected blood transfusion or organ transplant Animals can become infected in the same way, or they might eat an infected bug.
Medical Importance Affects an estimated 16-18 million people throughout South and Central America and Mexico. 50,000 die each year! In the United States only 5 cases have been reported in humans. Domestic transmission cycle, Southern Texas USA.
Case Study: San Benito, Texas Three pet dogs died from Chagas cardiomyopathy. Blood drawn from dogs and owners. A follow-up serologic survey was conducted. Inspection of the residence. Triatoma gerstaeckeri Domestic transmission cycle.
Signs and Symptoms There are three stages of infection in Chagas disease. (1) Acute Stage – 1% of cases –Romaña's sign – a person's eye on one side of the face swells, usually at the bite wound or where feces were deposited or accidentally rubbed into the eye. –fatigue, fever, enlarged liver or spleen, swollen lymph glands
Signs and Symptoms (2) Indeterminate Stage –8-10 weeks after infection –Once it begins it may last many years –people do not have symptoms. (3) Chronic Stage –10-40 years after infection 20-30% of infected people may develop the most serious symptoms of Chagas disease. –Cardiac problems, including an enlarged heart; altered heart rate or rhythm; heart failure; or cardiac arrest. –enlargement of the esophagus or large bowel, which results in problems with swallowing or severe constipation.
Diagnosis/Treatment Xenodiagnosis Medication for Chagas disease is usually effective when given during the early acute stage of infection. Once the disease has progressed to later stages, medication may be less effective. In the late chronic stages of infection, treatment focuses on managing the symptoms associated with the disease.
Prevention and Control Avoid sleeping in thatch, mud, or adobe houses. Use insecticides In some countries, the blood supply may not always be screened for Chagas disease. Bed Net with insecticides. Camp under cover.
Prevention and Control Control is based on spraying residual insecticides inside houses on walls, floors and roofs. Insecticidal Smoke Bombs Make the houses unattractive resting sites for bugs. –Plaster walls to cover up cracks. –Cost is high for rehousing.