Ventricular Worm Infestation in Kiwi Chicks

This blog/ case study summarises key themes and important information regarding two cases of fatal ventricular worm infestation in Northern Island Brown Kiwi chicks, Bingo and Sandee, at the Napier Kiwi Creche in early 2025.

Main Themes:

• Lethal Threat of Ventricular Worms: Both cases highlight the rapid and devastating impact of ventricular worms on kiwi chicks, leading to death despite intervention attempts. Bingo's autopsy revealed ventricular worms, which had caused havoc on the gizzard lining, leading to a soft, crumbly/eroded lining and internal bleeding.

• Challenges in Diagnosis and Early Detection: Initial symptoms can be subtle (e.g., slight dip in consumption) or misleading (e.g., initial thought of predator incursion for Bingo).

• Stool samples for ventricular worms can yield false negatives, as seen with Sandee, whose urgent stool sample returned a "negative result" despite a confirmed infestation post-mortem.

• Weight is a crucial indicator, but stones also have a weight value, which can complicate accurate assessment, as Kiwi will eat stones in an attempt to soothe the pain and irritation from the worms.

• Association with Pin Feather Stage: Both cases strongly suggest a correlation between the "pin feather stage" and the onset of severe ventricular worm infestations. Bingo was at this stage, and the "Changes to protocols?" section in both reports explicitly states, "Strategically dose all chicks at pin feather stage.” This seems to be when the ventricular worms strike. Sandee was NOT AT PIN FEATHER STAGE, PROBABLY GETTING CLOSE, suggesting proximity to this vulnerable period.

• Environmental Factors: The huge cicada emergence during the season is noted as a potential carrier of ventricular worms, indicating a possible environmental link to outbreaks.

• Stress as a Contributing Factor: Sandee's case points to stress as a potential exacerbating factor. She was described as "UNDER QUITE A BIT OF STRESS AS A WILD CHICK TAKEN SUDDENLY FROM ITS NATURAL ENVIRONMENT."

  
  

Left photo - Sandee and Right photo Bingo

Photo Credit Napier Kiwi Creche

Most Important Ideas/Facts:

Clinical Presentation:

• Weight Loss/Stagnation: The sign of something wrong will be in the chick's weight. Sandee experienced a "BOOM weight loss of 29g and zero consumption.

• Oral Indicators: A pale white mouth also indicates anaemia, observed in Sandee.

• Gastrointestinal Distress: Bingo's notes mention "can feel stones grinding in tummy." Bingo also had regurgitated/vomited up melena, indicating internal bleeding.

• Lethargy: Sandee was looking lethargic.

• Gizzard Damage: Autopsy of Bingo revealed a soft, crumbly/eroded lining in the gizzard, contrasting with the dull yellow and fairly smooth lining in healthy birds.

Confirmed Fatalities:

• Bingo (ID KW.Blew25): Female, 2 months old, died 17.3.25 from ventricular worm infestation. Incubated and hatched at Gallagher Kiwi Burrow, normal hatch, arrived at Napier Kiwi Creche.

• Sandee (ID Mt.Wu71c): Unknown sex, ~6 weeks old, died 10.3.25 from ventricular worm infestation. Wild chick found at nest site, estimated 14 days old on arrival at creche.

  
  

Photo Credit: Stuart Hunter

Treatment and Prophylaxis Attempts:

• Prophylactic moxidectin was given to Sandee when she showed signs of illness.

• Fluids also given to Sandee.

• Blanket doses of moxidectin were given after the death of Bingo and Sandee to protect the other kiwi chicks.

  
  

Revised Protocols and Recommendations (IN-HOUSE PROTOCOLS ONLY):

• Prophylactic Dosing at Pin Feather Stage: Strategically dose all chicks at the pin feather stage, which seems to be when the ventricular worms strike.

• Immediate Action on Suspicion: ASSUME VENTRICULAR WORMS, ESPECIALLY AT PIN FEATHERS STAGE AND ACT QUICKLY. VT WORMS ARE VICIOUS.

• Palpation for Stones: If you can feel stones in the gut, act immediately.

• Medical Cabinet Stocking: For our medical cabinet, we obtained Panacur, a broad-spectrum benzimidazole anthelmintic for the use if a chick/s appears unwell.

• Increased Weighing Frequency for Paired Birds: If you have paired birds, weigh them twice a week.

  
  

These cases highlight the aggressive nature of ventricular worms in kiwi chicks and the necessity for proactive, early intervention, particularly at the vulnerable pin feather stage.

This article was written by

Bev Wilkinson | Napier Kiwi Creche Manager