External Parasites External Parasites

External Parasites External Parasites Arthropod pests limit production in cattle industry Arthropod pests limit production in cattle industry

by affecting animals in many ways. by affecting animals in many ways. External parasites are the most serious threat External parasites are the most serious threat

since they feed on body tissues such as blood, since they feed on body tissues such as blood, skin and hair. skin and hair.

The wounds and skin irritation produced by The wounds and skin irritation produced by these parasites often result in discomfort and these parasites often result in discomfort and irritation for the animal. irritation for the animal.

More significant, however, is that any blood-More significant, however, is that any blood-sucking arthropod may transmit diseases from sucking arthropod may transmit diseases from infected animals to healthy ones. infected animals to healthy ones.

External parasites such as External parasites such as lice, flies, ticks, lice, flies, ticks, cattle grubs and mitescattle grubs and mites are a serious are a serious problem to livestock breeders. problem to livestock breeders.

These pests are most prevalent during These pests are most prevalent during spring and summer spring and summer months; however, months; however, southeast southeast Texas's warm climate permits Texas's warm climate permits many pests to live year-roundmany pests to live year-round. .

FliesFlies

Flies are characterized by Flies are characterized by having having one pair of wingsone pair of wings. . They have complete They have complete metamorphosis with metamorphosis with egg, egg, larva, pupa and adult larva, pupa and adult stages in their life history. stages in their life history. About 20 families of flies About 20 families of flies are of veterinary are of veterinary importance importance

House FlyHouse FlyCREDITS: J. F. Butler, University of Florida CREDITS: J. F. Butler, University of Florida

Comparison of the horn fly to the stable fly, house fly, and face fly. Photo: Photo: John B. Campbell, University of Nebraska-Lincoln

Horn Fly Horn Fly

The horn fly is one of the most The horn fly is one of the most serious pests of cattle in serious pests of cattle in Texas. It causes pain, Texas. It causes pain, annoyance and interference annoyance and interference with feeding, resting and other with feeding, resting and other normal activities. normal activities.

The fly pierces the skin to The fly pierces the skin to blood feed and is a persistent blood feed and is a persistent biter. biter.

With high summertime With high summertime populations, they cause cattle populations, they cause cattle to lose weight and lower milk to lose weight and lower milk production. production.

Horn flies may cause open Horn flies may cause open sores on the head and sores on the head and underline, which can underline, which can predispose the animals to predispose the animals to secondary infection. secondary infection.

Horn fly: greatest economic Horn fly: greatest economic loss in US cattleloss in US cattle

Horn flyHorn fly Eggs are laid exclusively in Eggs are laid exclusively in

fresh (within 10 minutes of fresh (within 10 minutes of dropping) cattle manure. dropping) cattle manure.

Larvae hatch in about 18 hours Larvae hatch in about 18 hours and feed on the dung, passing and feed on the dung, passing through 3 stages in 3 to 5 through 3 stages in 3 to 5 days. days.

The pupal stage lasts 3 to 5 The pupal stage lasts 3 to 5 days, and the adults which days, and the adults which emerge have a preoviposition emerge have a preoviposition period of 3 days. period of 3 days.

Mating takes place on the Mating takes place on the host, and females can lay host, and females can lay about 200 eggs in their about 200 eggs in their lifetime. The life cycle from egg lifetime. The life cycle from egg to adult takes about 10 to 14 to adult takes about 10 to 14 days days

Horse and Deer FliesHorse and Deer Flies

Horse flies and deer flies , also Horse flies and deer flies , also called Tabanids, are insects called Tabanids, are insects that are usually strong fliers. that are usually strong fliers.

As with mosquitoes, only As with mosquitoes, only females bite. females bite.

They are usually daytime They are usually daytime feeders and are vicious biters. feeders and are vicious biters.

Because of their painful bites Because of their painful bites and frequent attacks, horse and frequent attacks, horse flies produce frenzied behavior flies produce frenzied behavior in their hosts, sometimes in their hosts, sometimes causing them to run long causing them to run long distances in an effort to distances in an effort to escape. escape.

TabanidsTabanids

Tabanids introduce an anticoagulant into the Tabanids introduce an anticoagulant into the wound when they bite that causes blood to wound when they bite that causes blood to ooze. ooze.

These wounds are excellent sites for secondary These wounds are excellent sites for secondary invasion of other insects and diseases, and also invasion of other insects and diseases, and also cause more blood loss. cause more blood loss.

Being intermittent feeders, they can be important Being intermittent feeders, they can be important mechanical transmitters of diseases such as mechanical transmitters of diseases such as anthrax, tularemia and anaplasmosis. anthrax, tularemia and anaplasmosis.

Stable Flies Stable Flies

Bite wounds also can serve as Bite wounds also can serve as sites for secondary infection. sites for secondary infection.

These flies are easily These flies are easily interrupted in feeding and are interrupted in feeding and are mechanical transmitters of mechanical transmitters of anthrax and anaplasmosis anthrax and anaplasmosis

The stable fly, or dog fly, is The stable fly, or dog fly, is similar to the house fly in size similar to the house fly in size and color, but the bayonet-like and color, but the bayonet-like mouthparts of the stable fly mouthparts of the stable fly differentiate it from the house differentiate it from the house fly. fly.

Unlike the flies previously Unlike the flies previously discussed, both sexes of the discussed, both sexes of the stable fly are vicious biters. stable fly are vicious biters.

Stable flies cause irritation and Stable flies cause irritation and weakness in animals and weakness in animals and account for much blood loss in account for much blood loss in severe cases. severe cases.

Non-Blood Sucking FliesNon-Blood Sucking Flies Cattle Grubs Cattle Grubs

Two species of cattle grubs Two species of cattle grubs are found in the United States, are found in the United States, the common cattle grub and the common cattle grub and the northern cattle grub. the northern cattle grub.

The common cattle grub lays The common cattle grub lays its eggs chiefly on the hair of its eggs chiefly on the hair of cattle, attaching 5 to 15 eggs cattle, attaching 5 to 15 eggs to a single hair to a single hair

Eggs hatch within about 4 Eggs hatch within about 4 days, and the maggots burrow days, and the maggots burrow through the skin. through the skin.

Migration of the first stage Migration of the first stage larvae of the common cattle larvae of the common cattle grub is through connective grub is through connective tissue, assisted by enzyme tissue, assisted by enzyme secretion. secretion.

Cattle GrubsCattle Grubs The larvae produce two types of injury. The larvae produce two types of injury. --First there is irritation caused by larval migrations --First there is irritation caused by larval migrations

in the body of the host and later by emergence in the body of the host and later by emergence from beneath the skin. from beneath the skin.

--Second, the escape of the larva from the warble --Second, the escape of the larva from the warble leaves an open, running wound that is persistent leaves an open, running wound that is persistent and subject to secondary infection and subject to secondary infection

The grubs must be killed before they reach the The grubs must be killed before they reach the gullet or spinal cord, because killing grubs in gullet or spinal cord, because killing grubs in these areas can cause swelling, and paralysis or these areas can cause swelling, and paralysis or death death

Infestations of Fly Maggots Infestations of Fly Maggots (Myiasis) (Myiasis)

Myiasis is the presence of Myiasis is the presence of fly larvae in the living fly larvae in the living tissue of the host. tissue of the host.

Several kinds of maggots Several kinds of maggots infest the wounds of infest the wounds of warm-blooded animals; warm-blooded animals; however, the only one however, the only one that feeds exclusively on that feeds exclusively on live flesh is the primary live flesh is the primary screwworm screwworm

Lice Lice Most lice are permanent ectoparasites, spending their entire lives on Most lice are permanent ectoparasites, spending their entire lives on

the host. Both immature and adult stages are parasitic; therefore, the host. Both immature and adult stages are parasitic; therefore, they must remain on their hosts to survive. they must remain on their hosts to survive.

Sucking lice are found on the head, neck and brisket during winter Sucking lice are found on the head, neck and brisket during winter to early spring to early spring

Lice are generally transmitted from one animal to another by Lice are generally transmitted from one animal to another by contact. contact.

Transmission from herd to herd is usually accomplished by Transmission from herd to herd is usually accomplished by introduction of carrier animals introduction of carrier animals

MitesMites Mange mites (Mange mites (Psoroptes (most Psoroptes (most

damaging)damaging), , SarcopteSarcopte, and , and ChorioptesChorioptes) feed on the ) feed on the surface or burrow just beneath surface or burrow just beneath the skin, making very slender, the skin, making very slender, winding tunnels winding tunnels

The fluid discharged at the The fluid discharged at the tunnel openings dries to form tunnel openings dries to form nodules. A toxin is also nodules. A toxin is also secreted which causes intense secreted which causes intense irritation and itching irritation and itching

The infection may spread over The infection may spread over the entire body, forming large, the entire body, forming large, cracked scabs on the cracked scabs on the thickened skin thickened skin

Mange lesions Mange lesions

Mosquitoes Mosquitoes Mosquitoes are small insects Mosquitoes are small insects

with piercing-sucking with piercing-sucking mouthparts, and scales on mouthparts, and scales on their wings. their wings.

Female mosquitoes suck blood Female mosquitoes suck blood but do not always need blood but do not always need blood to lay the first batch of eggs. to lay the first batch of eggs.

Several species of mosquitoes Several species of mosquitoes attack livestock causing painful attack livestock causing painful bites, unthriftiness, and bites, unthriftiness, and occasionally death by occasionally death by suffocation or heavy blood loss suffocation or heavy blood loss

Ticks Ticks Ticks are easily distinguished from insects, since the body is not definitely Ticks are easily distinguished from insects, since the body is not definitely

divided and the strong fusion of the thorax and abdomen produces a sac-divided and the strong fusion of the thorax and abdomen produces a sac-like, leathery appearance. They belong to like, leathery appearance. They belong to the class Arachnida

A distinct head is lacking, but there is a head-like structure which bears A distinct head is lacking, but there is a head-like structure which bears recurved teeth that are inserted into the wound, allowing the tick to hold on recurved teeth that are inserted into the wound, allowing the tick to hold on strongly. strongly.

Females can be greatly distended and are bean-like in form when fully Females can be greatly distended and are bean-like in form when fully engorged. Ticks have 4 developmental stages: egg, 6-legged seed or larval engorged. Ticks have 4 developmental stages: egg, 6-legged seed or larval stage, 8-legged nymphal stage and 8-legged adult. stage, 8-legged nymphal stage and 8-legged adult.

Ticks Ticks The effects of ticks upon the The effects of ticks upon the

host include inflammation, host include inflammation, itching and swelling at the bite itching and swelling at the bite site, blood loss, production of site, blood loss, production of wounds that may serve as wounds that may serve as sites for secondary invasion, sites for secondary invasion, obstruction of body openings obstruction of body openings and paralysis from the injection and paralysis from the injection of toxic fluids. of toxic fluids.

They also transmit many They also transmit many diseases, including diseases, including anaplasmosis, bovine anaplasmosis, bovine piroplasmosis and tularemia. piroplasmosis and tularemia.

The cattle tick, The cattle tick, Boophilus microplus,Boophilus microplus, is a significant is a significant ectoparasite of cattle and a vector for important diseases ectoparasite of cattle and a vector for important diseases such as babesiosis and anaplasmosis. such as babesiosis and anaplasmosis.

B. microplusB. microplus requires high humidity and ambient requires high humidity and ambient temperatures of at least 15-20o C for egg laying and temperatures of at least 15-20o C for egg laying and hatching. hatching.

Differentiate fromDifferentiate from HaemophysalisHaemophysalis spp spp Ixodes holocyclusIxodes holocyclus

Keys To Pesticide SafetyKeys To Pesticide Safety

Before using any pesticide, stop and read the Before using any pesticide, stop and read the precautions. precautions.

Read the label on each pesticide container before each Read the label on each pesticide container before each use. heed all warnings and precautions. use. heed all warnings and precautions.

Store all pesticides in their original containers away from Store all pesticides in their original containers away from food or feed. food or feed.

Keep pesticides out of the reach of children, pets and Keep pesticides out of the reach of children, pets and livestock. livestock.

Apply pesticides only as directed. Apply pesticides only as directed. Dispose of empty containers promptly and safely.Dispose of empty containers promptly and safely.

Hemolytic SystemHemolytic System

Diseases Diseases

Babesiosis (Redwater fever)Babesiosis (Redwater fever)

This parasitic disease is usually first This parasitic disease is usually first reported in May/June when its tick host reported in May/June when its tick host first becomes active. first becomes active.

What is Babesiosis?What is Babesiosis?

Babesiosis is an infection of the red blood cells Babesiosis is an infection of the red blood cells by a single cell parasite of the genus Babesiaby a single cell parasite of the genus Babesia

Two important species in cattle— Two important species in cattle— BB bigeminabigemina and and BB bovisbovis

The disease is spread between cattle by ticksThe disease is spread between cattle by ticks The babesia is injected into the bloodstream by The babesia is injected into the bloodstream by

the tick and then invades the red blood cells and the tick and then invades the red blood cells and begins dividing, eventually rupturing the cell. begins dividing, eventually rupturing the cell.

Clinical signs begin around 2 weeks after Clinical signs begin around 2 weeks after infection.infection.

Boophilus annulatus: Vector for Babesia bigemina

Boophillus microplus: Vector for Babesia bovis

Clinical SignsClinical Signs

Increased temperature Increased temperature Diarrhea which ceases after around 36 Diarrhea which ceases after around 36

hours and then becomes constipation hours and then becomes constipation Red urine (due to haemoglobin produced Red urine (due to haemoglobin produced

by the rupture of the red blood cells) which by the rupture of the red blood cells) which becomes darker with time becomes darker with time

Increased pulse rate Increased pulse rate Abortion of pregnant cows Abortion of pregnant cows Death.Death.

DiagnosisDiagnosis

On the clinical signs described above On the clinical signs described above Recent movement to pastures known to Recent movement to pastures known to

harbour ticks harbour ticks Blood smears can show up the parasiteBlood smears can show up the parasite

Babesia in blood smear

TreatmentTreatment

Tetracyclines are the drug of choice for treating

Cattle dip for Babesia control

Prevention Prevention

Identification of risk areasIdentification of risk areasProphylactic treatment of cattle about to Prophylactic treatment of cattle about to be moved to a risk areabe moved to a risk areaTick controlTick controlVaccine not yet availableVaccine not yet available

Anaplasmosis Anaplasmosis Anaplasma marginale

Anaplasmosis is a vector-borne

infectious, hemolytic, rickettsial

disease of cattle, sheep, goats, and other

wild ruminants.

Young calves seem to have an innate resistance to the disease while the acute form generally occurs in cattle from 1 to 3 years.

In cattle over 3 years, the peracute or most severe form, with rapid onset and death, predominates.

Animals that survive anaplasmosis can become carriers for life and act as a reservoir of infection for susceptible animals.

-The disease commonly occurs during the

warm months when arthropod vectors, both

biological and mechanical are abundant.

-Ticks are the most important biological

vector

Biological transmission can occur with other vectors such as blood sucking flies (horse and stable flies) and mosquitoes.

Accordingly, humans can be a mechanical vector by using anaplasma-contaminated equipment such as scalpels, needles, and tatoo equipment on susceptible animals

SymptomsSymptoms Anaplasmosis is characterized by progressive Anaplasmosis is characterized by progressive

anemia due to extravascular destruction of anemia due to extravascular destruction of infected and uninfected erythrocytes infected and uninfected erythrocytes

Animals with peracute infections succumb within Animals with peracute infections succumb within a few hours of the onset of clinical signs. Acutely a few hours of the onset of clinical signs. Acutely infected animals lose condition rapidly infected animals lose condition rapidly

The urine may be brown but, in contrast to The urine may be brown but, in contrast to babesiosis, hemoglobinuria does not occur babesiosis, hemoglobinuria does not occur

BosBos indicusindicus breeds of cattle appear to possess a breeds of cattle appear to possess a greater resistance to greater resistance to AA marginalemarginale infection than infection than BB taurustaurus breeds breeds

Diagnosis Diagnosis Anaplasma marginale infection in bovine blood, Wright-Anaplasma marginale infection in bovine blood, Wright-

Giemsa, 100X oil immersion. Intracellular organisms Giemsa, 100X oil immersion. Intracellular organisms appear as basophilic, spherical inclusions that are appear as basophilic, spherical inclusions that are generally located near the margin of erythrocytes. generally located near the margin of erythrocytes. Frequent echinocytes are present. The hemat Courtesy Frequent echinocytes are present. The hemat Courtesy of Dr. John W. Harveyof Dr. John W. Harvey

Treatment:Treatment:

Tetracycline antibiotics and imidocarb are Tetracycline antibiotics and imidocarb are currently used for treatment.currently used for treatment.

Prompt administration of tetracycline drugs Prompt administration of tetracycline drugs (tetracycline, chlortetracycline, (tetracycline, chlortetracycline, oxytetracycline, rolitetracycline, oxytetracycline, rolitetracycline, doxycycline, minocycline) in the early doxycycline, minocycline) in the early stages of acute disease (eg, PCV >15%) stages of acute disease (eg, PCV >15%) usually ensures survival usually ensures survival

AnthraxAnthrax Anthrax is a zoonotic disease caused by the Anthrax is a zoonotic disease caused by the

sporeforming bacterium sporeforming bacterium BacillusBacillus anthracisanthracis . . Anthrax is most common in wild and domestic Anthrax is most common in wild and domestic herbivores (eg, cattle, sheep, goats, camels, herbivores (eg, cattle, sheep, goats, camels, antelopes) but can also be seen in humans antelopes) but can also be seen in humans exposed to tissue from infected animalsexposed to tissue from infected animals

BB anthracisanthracis spores can remain infective in soil spores can remain infective in soil for many years. During this time, they are a for many years. During this time, they are a potential source of infection for grazing livestock potential source of infection for grazing livestock

Feed contaminated with bone or other meal from Feed contaminated with bone or other meal from infected animals can serve as a source of infected animals can serve as a source of infection for livestock infection for livestock

Anthrax: Anthrax: Bacillus anthracisBacillus anthracis

Anthrax: TransmissionAnthrax: Transmission

Epidemiology: Epidemiology:

In the USA, anthrax has been reported In the USA, anthrax has been reported among domestic and wild animals nearly among domestic and wild animals nearly every year since records have been every year since records have been available. available.

BB anthracisanthracis has been manufactured as a has been manufactured as a biologic warfare agent. biologic warfare agent. BB anthracisanthracis was was used successfully as a weapon of used successfully as a weapon of terrorism in 2001, killing 5 people and terrorism in 2001, killing 5 people and causing disease in 22 causing disease in 22

Pathogenisis Pathogenisis

BB anthracisanthracis spores have a high affinity for spores have a high affinity for macrophages. After wound inoculation, macrophages. After wound inoculation, ingestion, or inhalation, spores infect ingestion, or inhalation, spores infect macrophages, germinate, and proliferate macrophages, germinate, and proliferate

As the bacteria multiply in the lymph nodes, As the bacteria multiply in the lymph nodes, toxemia progresses and bacteremia may ensue. toxemia progresses and bacteremia may ensue. With the increase in toxin production, the With the increase in toxin production, the potential for disseminated tissue destruction and potential for disseminated tissue destruction and organ failure increases organ failure increases

Anthrax: InhalationAnthrax: Inhalation

Anthrax spores

Clinical Findings:Clinical Findings:

Typically, the incubation period is 3-7 days Typically, the incubation period is 3-7 days (range 1−14 days). The clinical course (range 1−14 days). The clinical course ranges from peracute to chronic. The ranges from peracute to chronic. The peracute form (common in cattle and peracute form (common in cattle and sheep) is characterized by sudden onset sheep) is characterized by sudden onset and a rapidly fatal course. Staggering, and a rapidly fatal course. Staggering, dyspnea, trembling, collapse, a few dyspnea, trembling, collapse, a few convulsive movements, and death may convulsive movements, and death may occur in cattle, sheep, or goats with only a occur in cattle, sheep, or goats with only a brief evidence of illness.brief evidence of illness.

Diagnosis:Diagnosis:

A diagnosis based on clinical signs alone A diagnosis based on clinical signs alone is difficultis difficult

Specific diagnostic tests include bacterial Specific diagnostic tests include bacterial culture, and fluorescent antibody stains to culture, and fluorescent antibody stains to demonstrate the agent in blood films or demonstrate the agent in blood films or tissues. Western blot and ELISA tests for tissues. Western blot and ELISA tests for antibody detection are available in some antibody detection are available in some reference laboratories reference laboratories

Bacillus anthracis, methylene blue stain of tissue smear, high power. Bacillus anthracis, methylene blue stain of tissue smear, high power. Note the intense red stain of the large capsule of this organism and the Note the intense red stain of the large capsule of this organism and the large number of bacteria. Demonstration of the capsule distinguishes large number of bacteria. Demonstration of the capsule distinguishes

this from post-mortem contamination by a Cl Courtesy of the this from post-mortem contamination by a Cl Courtesy of the

Department of Pathobiology, University of GuelphDepartment of Pathobiology, University of Guelph

Bacillus anthracis, ground glass colonies. Courtesy of Dr. J. Glenn SongerBacillus anthracis, ground glass colonies. Courtesy of Dr. J. Glenn Songer

Treatment, Control, and Treatment, Control, and Prevention:Prevention:

Anthrax is controlled through vaccination Anthrax is controlled through vaccination programs, rapid detection and reporting, programs, rapid detection and reporting, quarantine, treatment of asymptomatic animals quarantine, treatment of asymptomatic animals (postexposure prophylaxis), and burning of (postexposure prophylaxis), and burning of suspect and confirmed cases.suspect and confirmed cases.

Livestock at risk should be immediately treated Livestock at risk should be immediately treated with a long-acting antibiotic to stop all potential with a long-acting antibiotic to stop all potential incubating infections. This is followed by incubating infections. This is followed by vaccination ~7-10 days after antibiotic treatment.vaccination ~7-10 days after antibiotic treatment.

Domestic livestock respond well to penicillin if Domestic livestock respond well to penicillin if treated in the early stages of the disease treated in the early stages of the disease

ReferencesReferences

http://edis.ifas.ufl.edu/ig130http://pods.dasnr.okstate.edu/docushare/http://pods.dasnr.okstate.edu/docushare/

dsweb/Get/Document-1932/VTMD-dsweb/Get/Document-1932/VTMD-7000web.pdf7000web.pdf