National Center for Veterinary Parasitology

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  • Home
  • Resources
    • People >
      • Directors and Advisory Board
      • Residents >
        • Boehringer Ingelheim Resident
        • Elanco Resident
        • IDEXX Resident
        • Merck Resident
        • Zoetis Resident
      • NCVP Alums
      • Clinical Parasitology Support
      • Additional Support
      • Sponsors
    • Parasite Image Database >
      • Protozoa
      • Arthropods
      • Nematodes
      • Trematodes
      • Cestodes
      • Acanthocephala
      • Tick-Borne Disease Agents
    • Case of the Month
    • Teaching and Research Materials >
      • Teaching Specimen Request
      • Parasite Jeopardy Games
      • Parasite Videos
    • Online Resources >
      • Parasitology Board Preparation
      • Additional Parasitology Resources
      • Resources for Educators
    • NCVP Board Member Resources
    • Residents' Corner
  • News
    • Veterinary Parasitology in the News
    • NCVP Newsletter
  • Opportunities
    • Request for Proposals
    • Residency Application
    • Continuing Education in Parasitology
    • Positions Open in Veterinary Parasitology

Case of the Month

October 2020

 

A scary finding.

These larvae were found near the tail head of a stray dog. The dog is approximately 2 years-old but no other history was available. The larvae were submitted to the diagnostic lab for identification. 
Picture
Image 1: Gross specimen. Lateral view (16 mm in length)
Picture
Image 2: Posterior end of larva showing spiracular plate. 
What's your diagnosis?
Diagnosis:
Lucilia sericata third instar.  Also called common green bottle fly.  Found throughout the world, but is more specifically described as having a Holarctic (Northern Hemisphere) distribution, being widely distributed throughout the United States and southern Canada. The larvae feed exclusively on carrion and excrement where they develop after hatching from eggs.  The larval stages can cause myasis in animals and humans.

Larvae: All stages are smooth, conical-shaped, and have a complete peritreme on the posterior spiracles. The larvae are white or yellowish through all three instars of development and reach a maximum of 12–18 mm before pupation.

Adults: The adults are usually a metallic green color and can also have a copper green hue. The back is hairy and the overall diameter is about 8–10 mm. 
Picture
​Posterior segment with two spiracles (three slits per spiracle = third instar), distance between each papilla (P) similar to distance between P1 and P2.  Complete peritreme (black arrow) and central button (blue arrow). 

September 2020

 

Does this belong in a camel?

​A routine fecal egg count was requested on a 2-year-old camel during the month of August.  A Wisconsin was performed and the following parasite egg was observed:   
Picture
Image 1: Egg measures 75 µM x 65µM
What's your diagnosis?
Spurious Toxocara cati

This camel ingested food contaminated with cat feces. The egg is fully larvated  which means the egg has been in the environment for a few weeks.  We know the egg is T. cati due to its size.. 

Camels have been reported to be infected with roundworms in other parts of the world, the species that infects them is Toxocara vitulorum (75 to 90 µM x 60 to 75µM), and it is commonly found in the small intestine of bovid calves in tropical and subtropical regions of the world.  

Camels and adult bovines can become infected with Toxocara vitulorum after ingesting eggs from the environment.  In calves the most common route of transmission is lactogenic. Treatment is recommended in young calves, however treatment in adult bovines is unlikely to be effective because of the inability of the drugs to affect hypobiotic larval forms. 

​Treating the camel for the spurious ​Toxocara cati egg is not necessary as it is not a true parasite of camels. 

August 2020

 

​Eggs and worms and teeth, oh my!

​A 4-month-old German shepherd was submitted for necropsy to the Oklahoma Animal Disease Diagnostic Laboratory. The dog had a history of hematochezia, anemia, and lethargy. The intestinal content was used to perform a centrifugal fecal flotation with Sheather’s solution. The following eggs and part of a worm were observed.
Picture
Image 1: 100X magnification
What's your diagnosis?
Ancylostoma caninum is the most common hookworm of dogs. Adults live in the small intestine, and their buccal cavity is armed with three pairs of teeth that are used to attach to the intestinal mucosa. They are voracious blood feeders, which gives them their dark colored appearance in fresh specimens. Peracute, acute, and chronic disease syndromes can occur. Transmission is via several routes: direct skin penetration or ingestion of infective third-stage larvae in the environment,  ingestion of a paratenic host with infective larvae in its tissues, or transmammary transmission to pups.
 
The eggs can be detected by flotation techniques, and measure 60–79 x 30–55um.

​
Picture
Image 2: Anterior end of adult worm with an egg visible in its buccal cavity.

July 2020

 

Somebunny has parasites...

A fecal sample from a 4 month-old intact male English lop rabbit was submitted for gastrointestinal parasite evaluation.  According to the owner, the rabbit has not been doing well lately. 

A centrifugal fecal flotation with Sheather’s sugar solution (specific gravity, 1.26) was performed, and a number of these eggs were observed (Images 1–3) sizes ranged from 97.5 x 40 µM to 105 x 47.5 µM
Picture
Image 1: 100x magnification
Picture
Image 2: 200x magnification 
Picture
Image 3: 400x magnification
What's your diagnosis?
Passalurus ambiguus

Passalurus ambiguus are Oxyurids, commonly called pinworms and are distributed worldwide. The adults live in the cecum of rabbits. The eggs are passed in the feces of infected rabbits, and the eggs become infective within a short period of time.  Infections with this nematode are usually subclinical.

The eggs can be detected by flotation techniques, and measure 95-105 x 45 µM.   

June 2020

 

The chicken or the egg?

Three chickens were submitted for necropsy to the Oklahoma Animal Diseases Diagnostic Laboratory.  A history of poor feather condition, decreased egg production, and increased mortality was reported. The ceca of the birds were submitted for fecal examination and parasite identification. During gross examination several adult parasites were observed in one of the chicken’s cecum (Figures 1–3).
The fecal content was pooled for a centrifugal fecal floatation using sugar solution and the following eggs were observed (Figures 4 and 5). 
What's your diagnosis?
Heterakis spp.  

Heterakis spp. are common parasites in poultry and wild bird hosts.  Adults are found in cecum.  Eggs are passed in the feces of poultry and become infective in the environment.   
 
How were the chickens infected? Ingesting eggs from contaminated environment or through ingestion of earthworms that act as transport host.  

Is it pathogenic? Heterakis gallinarum is usually nonpathogenic, however they act as vectors of the protozoan Histomonas melagridis (blackheaded disease) which can be a life threatening infection, particularly in turkeys. 

How do you treat it? Piperazine is an anthelmintic approved by the FDA for use in chickens to treat ascarids.  Fenbendazole has also been shown to reduce the number of Heterakis gallinarum in infected birds by less than 90%. (1, 2)
 
Reference:
  1. Yazwinski TA, Tucker CA, Wray E, Jones L, Clark FD. Observations of benzimidazole efficacies against Ascaridia dissimilis, Ascaridia galli, and Heterakis gallinarum in naturally infected poultry. J Appl Poult Res. 22:75–79; 2013. 
  2. Coles GC, Bauer C, Borgsteede FHM, Geerts S, Klei TR, Taylor MA, Waller PJ. World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) methods for the detection of anthelmintic resistance in nematodes of veterinary importance. Vet Parasitol. 44:35–44; 1992.

May 2020

 

Rats!

A fecal sample from a 2 year-old male rat rescued from a hoarding situation, was submitted for gastrointestinal parasites evaluation. The rat did not show any symptoms at submittal but the feces was soft in consistency.

For fecal analysis, a centrifugal fecal flotation with Sheather’s sugar solution (specific gravity, 1.26) was performed, and a low number of eggs were observed.
Picture
What's your diagnosis?
Trichosomoides crassicauda or bladder threadworm, is a parasite of the urinary bladder of rats. The female is 10–19 mm long; the male measures 1.5–3.5 mm.  A curious fact about this parasite is that the male lives inside the uterus of its mate (hyperparasite).  

The medium‐sized egg is lemon‐shaped with transparent polar plugs and measures about 60–70 by 30–36 μm. The shell is thick and brown, and contains either a morula or an L1 larva. 
 
How did the rat become infected? Usually from mother rats to their offspring before weaning. 

Is it pathogenic? The presence of the worms can cause nodules in the bladder wall.
 
How do you treat it? In laboratory animals successful treatment has been achieved with Ivermectin subcutaneously at 0.2 mg/kg or orally at 3mg/kg.
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