4Arachnida Ticks (Ixodida) ●They are blood-sucking, opportunistic parasites that can attach to the skin of a variety of vertebrate hosts.● They have no segmentation and are dorso-ventrally flat with four pairs of legs
5● All stages of the tick life cycle can suck blood, it is normally the adult tick that poses a problem for humans.The order metastigmata includes two important families,Argasidae (soft ticks)Ixodidae (hard ticks)The latter is the most significant group worldwide
6● The most important species is Ixodes ricinus ●Approximately 20 hard tick species are indigenous to western and central Europe, belonging to the genera Ixodes, Rhipicephalus, Dermacentor, and Haemaphysalis.● The most important species isIxodes ricinusthat accounts for about 90% of the tick fauna in this region.
7Ixodes ricinus● Vector of the causative agents of Lyme borreliosis and Tickborne encephalitis● Human tick bites in central Europe are in most cases caused by I. ricinus and only occasionally by other tick species.
8Morphology.Male: About 2–3mm long with a highly chitinized scutum covering the entire dorsal surface.Female: 3–4mm, up to 12mm when fully engorged after a blood meal; the scutum covers only the anterior portion of the body..
10● Ticks possess characteristic piercing mouthparts. ● Adults and nymphs have four pairs of legs, the smaller larvae (about 0.5mm long)has only three pairs of legs● Ticks possess characteristicpiercing mouthparts.
12● The various stages of I ● The various stages of I. ricinus are dependent on blood meals from vertebrates throughout their developmental cycle. Having selected a suitable location on a host, a female tick inserts her piercing mouthparts into the skin within about 10 minutes.● Using clawlike organs at the tip of stylettelikemouthparts, the chelicerae, the tick cuts a wound into which the unpaired,barbed, pinecone-shaped hypostome is then inserted to anchor the parasite in the skin.
13female engorged with blood ● While sucking blood, ticks secrete large amountsof saliva,containing cytolytic, anticoagulative, andother types of substances. They ingest blood, tissuefluid and digested tissue components.● The weight of the femaleincreases considerablyduring a blood meal.When completely engorgedthe tick resembles aricinus seed.Ixodes ricinusfemale engorged with blood
14The epidemiologically important factor is the EpidemiologyThe epidemiologically important factor is thepossible ingestion of pathogens with the bloodmeal, which can, at a following blood meal in thetick’s next developmental stage, be inoculatedinto another vertebrate host (horizontaltransmission).Female ticks even transmit certain pathogens bythe transovarial route to the next generation ofticks (vertical transmission).
15Developmental stage Host groups commonly used for blood feeding Egg--LarvaRodents,birds,humansNymphBirds,mamals,humanImago(Adult)Domestic and wild ruminants,dogs, cats,horses, and other animal species,humansRodents,birds,humans
16In northern and eastern Europe the TBE The great epidemiological significance ofI.ricinus in central Europe is predominantly due to its function as vector of the causative agents of Lyme borreliosis (Borrelia burgdorferi ) and the European tickborne encephalitis (TBE)In northern and eastern Europe the TBEvirus is transmitted by Ixodes persulcatus.
17DISEASES FOR WHICH HARD TICKS ARE CARRIERS BACTERIAL DISEASES Rocky Mountain Spotted FeverThe causative agent,Ricketsia rickettsii, iscarried by the Brown Dog tick and theRocky Mountain Wood Tick (the twoDermacentor species )
18DISEASES FOR WHICH HARD TICKS ARE CARRIERS BACTERIAL DISEASES TularemiaOne of the several ways that humans can be infected is by being bitten by a tick that has acquired the bacterium after biting one of a rodent carryıng Francisella tularensis
19DISEASES FOR WHICH HARD TICKS ARE CARRIERS BACTERIAL DISEASESQ FeverVarious farm animals (cattle sheep goats etc) are the primary carriers of the bacterium Coxiella burnetii which causes Q fever.Spread to humans is usually via inhalation of dust containing dried urine, feces etc of infected animals. However, less commonly, the bacterium can be transmitted via the bite of Dermacentor ticks .
20Q Fever Clinical manifestation Acute Q fever Many patients, about half, show no signs of infection butin others after an incubation period of weeks, thereis a sudden onset of fever, headache, general malaise,myalgia, sore throat, chills, sweats, non-productivecough, nausea, vomiting, diarrhea, abdominal pain, andchest pain.The patient may also appear confused. Many patientsgo on to the symptoms of pneumonia and hepatitis butmost recover in a month or two without treatmentalthough acute Q fever has a mortality rate of 1-2%.
21Q FeverChronic Q feverIf the patient fails to resolve the infection, chronicQ fever results. This can occur a few months afterprimary infection but can also occur many yearslater.Endocarditis of the aortic heart valves is the majorproblem that arises. This usually occurs in peoplewith heart valve disease but also at risk aretransplant, cancer and kidney disease patients. The chronicform of Q fever has a fatality rate of about %.
22Q Fever Diagnosis Treatment Serology to determine the presence of antibodies againstCoxiella burnetii is used. TreatmentAntibiotics such as doxycyline are used to treat acute Q fever. For chronic Q fever, two protocols have been İnvestigated doxycycline along with quinolones for at least 4 years and doxycycline with hydroxychloroquine for 1.5 to 3 years.There is a vaccine used in Australia for persons who may come in contact with C. burnettii but it is not commercially available in the United States.
23DISEASES FOR WHICH HARD TICKS ARE CARRIERS BACTERIAL DISEASES Human erlichiosisis carried by Dermacentor variabilis and byAmblyomma americanum and is caused by anumber of bacteria of the Ehrlichia family .As with many tick-borne diseases, incidence followsvector distribution with higher incidence during thesummer months when tick populations and contactwith them are higher .
24DISEASES FOR WHICH HARD TICKS ARE CARRIERS BACTERIAL DISEASESLyme DıseaseLyme disease is caused by the spirochete bacterium,Borrelia burgdorferi which typically infects small mammals in the northeast and north central United States.It is transmitted to humans by Ixodid black legged ticks .There are over 20,000 cases per year in the United States making it the most common tick-borne disease in North America.In Europe, a similar disease is caused by Borrelia garinii or Borrelia afzelii.
26Lyme Disease Clinical manifestation Fever, headache and malaise and characteristic rash named erythemia migrans which can occur in a few days but sometimes only after a few weeks, are typical of Lyme Disease.The rash often has a bull’s eye appearance since as it grows ,the central region clears. If left untreated, the infection spreads and can result in Bell’s Palsy(partial paralysis of muscles in one or both sides of the face), meningitis, heart palpitations and severe joint pain.
27Lyme Disease These symptoms usually resolve in a few weeks but after several months about 60%of patients will get severe joint swelling andarthritis. A small minority may also getneurologic symptoms.DiagnosisVarious laboratory tests include Elisa,Western blot
28Lyme Disease Treatment Early administration with antibiotics (doxycycline, amoxicillin, or cefuroxime axetil)is recommended.Some patients continue with neurological andmuscle pain problems even after antibiotictreatment. It is not known what causes thesebut they may be autoimmune in nature.
29DISEASES FOR WHICH HARD TICKS ARE CARRIERS VIRAL DISEASESCrimean-Congo Hemorrhagic FeverCaused by a Nairovirus, a member of the Bunyaviridae. It is found in Eastern Europe and throughout the Mediterranean areas of southern Europe, the Middle East, Africa,China central and south Asia..
30Crimean-Congo Hemorrhagic Fever Ixorid ticks (genus Hyalomma) spreadthe virus, which is also carried bynumerous species of domestic and wildanimals.Person to person transmissionThrough infected blood and other bodyfluids hasbeen documented.
31Crimean-Congo Hemorrhagic Fever Clinical manifestationInitially, the patient presents with headache, high fever,back pain, joint pain, stomach pain, and vomiting.There may be flushing, red eyes and throat and smallred spots called petechiae on the palate. Hemorrhageensues after a few days and lasts for a few weeks .This is indicated by severe bruising, nosebleeds, andfailure to stop bleedings after a cut or injection.Slow recovery often ensues but mortality can be as highas 50%.
32Crimean-Congo Hemorrhagic Fever TreatmentSince this is a viral disease,Treatment is largely supportive with particular attention to electrolyte balance.Ribavirin has been used.An inactivated vaccine has been used in Eastern Europe.
33Crimean-Congo Hemorrhagic Fever Virus in High-Risk Population, Turkey In the Tokat and Sivas provinces of Turkey, the overall Crimean-Congo hemorrhagic fever virus (CCHFV) seroprevalence was 12.8% among 782 members of a high-risk population. CCHFV seroprevalence was associated with history of tick bite or tick removal from animals, employment in animal husbandry or farming, and being >40 years of age.Turabi Gunes, Aynur Engin, Omer Poyraz, Nazif Elaldi, Safak Kaya, Ilyas Dokmetas, Mehmet Bakir, and Ziynet Cinar Cumhuriyet University, Sivas, TurkeyCDC March 2009
34DISEASES FOR WHICH HARD TICKS ARE CARRIERS VIRAL DISEASESTıck -Born EncephalitisThis disease results from infection by tick-borne encephalitis virus, which is a member of the Flaviviridae. Clinical manifestationTick-borne encephalitis starts as mild influenza-like symptoms with fever accompanied by leuko and trombocytopenia. This resolves within a few days. However, about one third of patients develop meningitis and meningoencephalitis. This can, in a few cases, be followed by paralysis.
35Tıck -Born Encephalitis The European form of the disease has a mortality rate of under 5%. Most patients recover but about a third may have long lasting Neurological problems.TreatmentSupportive is indicated. There is an experimentalkilled vaccine in Europe. In Sweden TBE vaccination is recommended for residents of and regular visitors to TBE endemic areas.
36Tick bite preventionTick habitats with dense undergrowth, ferns, and high grasses should be avoided as far as possible. If this is unavoidable, proper clothing must be worn: shoes, long socks, long trousers (tuck legs of trousers into socks), long sleeves that fit closely around the wrists.Additional protection is provided by spraying the clotheswith acaricides, especially pyrethroids,which havea certain repellent effect (e.g., flumethrin). The effect of repellents applied to the skin (for malaria) is in most cases insufficient to protect against ticks.
37Tick bite preventionAfter staying in a tick habitat persons should search their entire body for ticks and remove any found attached to the skin as quickly as possible by mechanical means (do not apply oil or other substances to attached ticks
39Tick bite preventionAny bites should be watched during the following four weeks for signs of reddening (erythema), swelling, and inflammation.A “migrating,” spreading rash (erythema migrans) is indicative for a Borrelia infection.On the other hand, this sign is not observed in all infected persons.
40Sarcoptes scabiei Causative agent of scabies MitesSarcoptes scabiei Causative agent of scabiesScabies mite (Sarcoptes scabei) is the cause of scabies and is distributed worldwide. Epidemics of the disease may occur for long periods but mites may be common at all times in very poor communities with inadequate washing facilities.
41Life cycle of the Scabies mite (Sarcoptes scabei) EggLarvaNymphAdult
42Sarcoptes scabei1-Females deposit eggs at 2 to 3 day intervals as theyburrow through the skin . Eggs are oval and 0.1 to0.15 mm in length and incubation time is 3 to 8 days. 2-After the eggs hatch, the larvae migrate to the skinsurface and burrow into the intact stratum corneum toconstruct almost invisible, short burrows called moltingpouches.
43Sarcoptes scabei3-The larval stage, which emerges from the eggs, has only 3 pairs of legs , and this form lasts 2 to 3 days. After larvae molt, the resulting nymphs have 4 pairs of legs . This form molts into slightly larger nymphs before molting into adults.4-Larvae and nymphs may often be found in molting pouches or in hair follicles and look similar to adults, only smaller.
44Sarcoptes scabei Adults are round, sac-like eyeless mites. Females are 0.3 to 0.4 mm long and 0.25to 0.35mm wide, and males are slightly more than halfthat size. Mating occurs after the male penetrates the molting pouch of the adult female
45Sarcoptes scabeiImpregnated females extend their molting pouches into the characteristic serpentine burrows, laying eggs in the process. The impregnated females burrow into the skin and spend the remaining 2 months of their lives in tunnels under the surface of the skin. Males are rarely seen. They make a temporary gallery in the skin.
47Sarcoptes scabei Epidemiology. Transmission is by close contact (sexual partners, family,members, school children, healthcare staff) from person to person,Indirect transmission on clothes (underclothes), bed linens is not a primary route, but should be considered as a factor in control measures.Without a host, mites usually die off within a few days. Mite infections can also be acquired from animals to which humans have close skin contact.
48Sarcoptes scabei infestation with Sarcoptes mites is the primary Clinical manifestations. An early sign of an initialinfestation with Sarcoptes mites is the primaryefflorescence with mite tunnels up to 2–4mm andsometimes 10 mm long threadlike, irregularly .The female mite is found at the end of the burrow in asmall swelling.Following an inapparent period of about four to fiveweeks, during whith time a hypersensitivity response tomite antigens develops
50Sarcoptes scabeiThe scabies exanthema manifests in the form of local or generalized pruritus, which is particularly bothersome in the evening when body heat is retained under the bedcovers.The evolving skin lesions are papulous orapulovesicular exanthema and reactions due to scratching.In adults, these lesions are seen mainly in the interdigital spaces and on the sides of the fingers, on the wrists and ankles and in the genital region. Children also occasionally show facial lesions.
51Sarcoptes scabei Diagnosis and control Case history and clinical manifestations provide important diagnostic hints that require etiological confirmation by identification of the parasites.Mites can be isolated from skin tunnels after scarification with a needle or by pressing adhesive tape onto the skin.
52Sarcoptes scabei A papule is removed by tangential scalpel excision, upon the specimen is macerated in 10% potassiumhydroxide (KOH), and then examined for mites undera microscope. Mites can also be isolated from skintunnels after scarification with a needle or by pressingadhesive tape onto the skin.
56Sarcoptes scabei Treatment Therapy requires topical application of c-hexachlorocyclohexane (lindane), permethrin or crotamiton in strict accordance with manufacturer’s instructions.A recent development is peroral therapywith ivermectin. Underclothing and bed linens must be washed at a minimum temperature of 50 8C.