Nematode: Superfamily Filarioidea

-ID: LONG THIN NEMATODES

-LC: INDIRECT

-IS: L3 FROM INSECT

General Characteristics fo Superfamily Filarioidea
-ID
-LC
-IS

Microfilaria (mf) larvae

What do females of superfamily Filarioidea lay

in the intermediat host

Where do microfilaria develop into an infectious L3?

-common name: HEARTWORM

-host: DOGS, CATS, OTHER MAMMALS, IH: MOSQUITOES

-adult ID: TAPERED HEAD, STRAIGHT TAIL, WIDER THAN RBC 30 CM

-egg ID: MF ~300 µm

-Life cycle: INDIRECT

-Infective Stage: L3 IN MOSQUITO

-PPP: 6-9 MONTHS

-Site of Infection: SQ TISSUE (L3/L4) -> PULMONARY ARTERIES (ADULT) -> PERIPHERAL BLOOD (MF)

-Transmission: PERCUTANEOUS -> MOSQ BITES AND L3 TRAVELS INTO BITE TO INFECT HOST

-Diagnosis: ADULTS- ANTIGEN TEST; MF- BLOOD SMEAR, KNOTS TEST; RADIOGRAPH; ECHO

**SO BOTH ANTIGEN AND BLOOD

-Pathogenesis: L5/IA- HYPERTROPHY, THICKENING OF VESSELS, PULMONARY A. DAMAGE, PULMONARY HYERTENSION

-Clinical Signs: ASYMPTOMATIC, MILD COUGH, EXERCISE INTOLERANCE, DEATH

-Treatment: RESISTANCE

TEST BEFORE TX

L3/L4: MONTHLY PREVENTATIVE STARTING FROM 8 WEEKS OF AGE

L5/IA: MELARSOMINE (2-3 INJ.)

MF: MOXIDECTIN

WOLBACHIA: ANTIBIOTICS

PREVENT MOSQUITO FEEDING

-Zoonotic: RARE

Dirofilaria immitis
-common name
-host
-adult ID
-egg ID
-Life cycle
-Infective Stage
-PPP
-PPR
-Arrested stage
-Site of Infection
-Transmission
-Diagnosis
-Pathogenesis
-Clinical Signs
-Treatment
-Zoonotic

Mosquito ingest MF -> MF TO L3 in mosquito -> Mosquito bites dog -> L3 gets deposited on skin and travels into bite -> enter SQ tissues -> mature into L5 -> migrate to Cadual Pulmonary aa. -> mature into adults -> female release MF into blood

Describe the life cycle of Dirofilaria immitis

3 years

How long can MF of heartworms circulate in the blood?

during the summer months (mosquito season)

When do we see an increased in occurence of Dirofilaria immitis

6+ months

How long does it take for L3 of Dirofilaria immitis to mature into adults in the pulmonary aa?

6 to 9 months

How long till we see L3 of Dirofilaria immitis mature into adults and start depositing mf into blood?

L5/IM

What stage does pathology associated with Dirofilaria immitis start?

at soon as 4 months post infection with L3

When does pathology of Dirofilaria immitis start?

Need female worms! This will occur ~ 6 months post infection.

What stage must be present for an antigen test for Dirofilaria immitis

Small dog because they have a small blood:worm ratio making us more likely to find the antigens

Would an antigen test be most sensative with a small or large dog?

When you have an antigen bound by an antibody is is not tectable by the antigen test, thus giving you a false negative.

What is the issue with antigen tests for Dirofilaria immitis

heat treat the blood to breka up the antibody-antigen bond- increases by 10%

What is an option for imporiving the sesativity of diagnostics for Dirofilaria immitis?

>9 months

When do we start viewing MF of Dirofilaria immitis in peripheral blood?

the larvae will wiggle in place and not advance forward

What is a key feature to look for when doing a Dirofilaria immitis blood smear?

it concentrates the larvae and can be stained for ID

What is the benefit of doing a Knott's test?

They are cyclic! The mf will be more prevelant at dusk and dawn when mosquitoes are more likely to be feeding.

What is special about Dirofilaria immitis mf prevelance

1. you can have occult infection = infections without mf
2. mf can be supressed when you are treating with MCLs

What are 2 issues with relying on mf for Dirofilaria immitis diagnosis?

antigen + mf testing

What diagnosis method should be used always? Even at yearly exams!

they are used in supplement to understand serverity of infection

Why do we also use radiographs and enchos for Dirofilaria immitis diagnosing?

1. MCL monthly to kill L3/L4
2. 6/12 month injection
3. start preventative at 8 weeks

3 methods to preventing Dirofilaria immitis adults

Because after 4 weeks the hwt larvae are out of the l3/l4 development stage and are no longer treatable using a adult preventative

Why would it be ideal for us to make a preventative for a 4 week old puppy?

1. improve clinical condition
2. eliminate all stages in the dog
3. minimal post-tx complications

3 goals of adult Dirofilaria immitis treatment in dogs

1. dead asnd dying worms can worsen inflammation can cause sever lung disease
2. symbiont Wolbachia spp. (bacteria) can contribute to pathology when Dirofilaria immitis are killed

2 complicationg with treating for adult worms in Dirofilaria immiti

Wolbachia plays a role in development of Dirofilaria immitis

What is the symbiotic role of Wolbachia spp. bacteria with Dirofilaria immitis

1. stabilize the dog
2. prevent further infection, kill L3/L4, place on preventative
3. kill l5/immature adult/adult worms with 2-3 inj. melarosomine
4. kill mf with mocidectin

5 steps to treating adult Dirofilaria immitis in dogs

L3/L4, MCL

What stage of Dirofilaria immitis is developing resistance? What are they becoming resistant to?

-suspectability to infection: very high (~100%)
-longevity of worms: 5-7 yr
-adult worms: not uncommon to find >30
-single sex infection: unusual
-mf: persistent, very common
-organ with greatest pathology: heart, lungs
-clinical importance: less clinically important, depending upon the size/evercise level of the dog
-diagnosis: simple
-treatment: one compound approves, manageable complicaitons

Dog Dirofilaria immitis
-suspectability to infection
-longevity of worms
-adult worms
-single sex infection
-mf
-organ with greatest pathology
-clinical importance
-diagnosis
-treatment

-suspectability to infection: lower (~75to90%)
-longevity of worms: 2-3 yr
-adult worms: usually <6
-single sex infection: common
-mf: transient
-organ with greatest pathology: lungs
-clinical importance: potentially fatal
-diagnosis: complex
-treatment: non approved, high risk of complications

Cat Dirofilaria immitis
-suspectability to infection
-longevity of worms
-adult worms
-single sex infection
-mf
-organ with greatest pathology
-clinical importance
-diagnosis
-treatment

-host: DOGS, IH: FLEAS, LICE, TICKS

-MF ID: BLUNT HEAD, CURVED TAIL, THINNER THAN RBC

-Site of Infection: ADULT - SQ TISSUE, MF- PERIPHERAL BLOOD

-Diagnosis: MF (L1) IN BLOOD,

-Pathogenesis: NONE

-Clinical Signs: NONE

Acanthocheilonema reconditum
-host
-MF ID
-Infective Stage
-Site of Infection
-Diagnosis
-Pathogenesis
-Clinical Signs

-host: EQUIDS, IH: MOSQUITO

-adult ID: LONG, SLENDER, 8-12 CM

-Site of Infectionl ADULT- PERITONEAL CAVITY, MF-PERIPHERAL BLOOD

-Diagnosis: ADULTS SEEN DURING SURGERIES

-Pathogenesis: NONE

-Clinical Signs: NONE

-Treatment: NONE

Setaria equina
-host
-adult ID
-Site of Infection
-Diagnosis
-Pathogenesis
-Clinical Signs
-Treatment

-common name: THREADWORM

-host: EQUID

-adult ID: SLENDER, 2-6 CM, IH- CULICOIDES SPP. (NO SEE 'EMS)

-Site of Infection: ADULTS- COILED IN TISSUE NODULES, MF- TISSUE SPACES OF SKIN

-Diagnosis: SKIN BIOPSY

-Clinical Signs: DERMITITIS- PRURITIC, SCALES, CRUSTS, ALOPECIA, ULCERATION

-Treatment: ADULTS- NONE, MF-MCL

Onchocerca cervicalis
-common name
-host
-adult ID
-egg ID
-Life cycle
-Infective Stage
-PPP
-PPR
-Arrested stage
-Site of Infection
-Transmission
-Diagnosis
-Pathogenesis
-Clinical Signs
-Treatment

Habronema spp. and Draschia Megasoma spp.

What is Onchocerca cervicalis often confused with

Summer sores will be a circular inflammed area that come and go. While Onchocerca cervicalis is often irregular lesions with various symptoms

How to differentiate Onchocerca cervicalis with Habronema spp./Draschia Megasoma spp.