Recurrent patent infections with Toxocara canis in household dogs older than six months

a prospective study

Rolf Nijsse*, Lapo Mughini-Gras, Jaap A. Wagenaar, Harm W. Ploeger

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

5 Citations (Scopus)

Abstract

Background: To reduce environmental contamination with Toxocara canis eggs, the current general advice is to deworm all dogs older than six months on average four times a year. However, only a small proportion of non-juvenile household dogs actually shed T. canis eggs, and some dogs shed eggs more frequently than others. The identification of these frequent shedders and the associated risk factors is an important cornerstone for constructing evidence-based deworming regimens. The purpose of this study is to identify risk factors associated with recurrence of periods of shedding Toxocara eggs in a cohort of household dogs older than six months. Methods: We performed a prospective study (July 2011 to October 2014) on shedding Toxocara eggs in a cohort of 938 household dogs older than six months from all over the Netherlands. The median follow-up time was 14 months. Monthly, owners sent faecal samples of their dogs for Toxocara testing and completed a questionnaire. Dogs were dewormed only after diagnosis of a patent infection (PI). Survival analysis was used to assess factors influencing the time to first diagnosed PIs (FPI) and the time to recurrent PIs (RPI). Results: The overall prevalence of PIs was 4.5 %, resulting in an estimated average incidence of 0.54 PIs/dog/year. No PI was diagnosed in 67.9 % of the dogs, 17.5 % of the dogs went through only one PI and 14.6 % had > 1 PI. Prevalence of PIs always peaked during wintertime. Increased hazards for first diagnosed PIs were associated with coprophagy, geophagy, walking off-leash for = 80 % of walking time, reported worms in the faeces, feeding a commercial diet and suffering from urologic or respiratory conditions. Median time to reinfection was nine months. Factors associated with increased hazards for recurrent PIs were taking corticosteroids, changing dog's main purpose, and proxies for veterinary care-seeking behaviours. Conclusions: We concluded that targeted anthelmintic treatments in household dogs may be feasible as PIs tend to (re)occur in specific periods and in groups of dogs at high risk. Moreover, recurrent PIs appear to be influenced more by factors related to impaired immunity than environmental exposure to Toxocara eggs.

Original languageEnglish
Article number531
Number of pages11
JournalParasites & Vectors
Volume9
Issue number1
DOIs
Publication statusPublished - 2016

Fingerprint

Toxocara canis
Prospective Studies
Dogs
Infection
Toxocara
Eggs
Walking
Coprophagia
Anthelmintics
Environmental Exposure
Proxy
Survival Analysis
Feces
Netherlands

Keywords

  • Deworming
  • Dogs
  • Longitudinal study
  • Recurrent patent infections
  • Toxocara canis

Cite this

Nijsse, Rolf ; Mughini-Gras, Lapo ; Wagenaar, Jaap A. ; Ploeger, Harm W. / Recurrent patent infections with Toxocara canis in household dogs older than six months : a prospective study. In: Parasites & Vectors. 2016 ; Vol. 9, No. 1.
@article{9902607242c14cdfac89b307393bff88,
title = "Recurrent patent infections with Toxocara canis in household dogs older than six months: a prospective study",
abstract = "Background: To reduce environmental contamination with Toxocara canis eggs, the current general advice is to deworm all dogs older than six months on average four times a year. However, only a small proportion of non-juvenile household dogs actually shed T. canis eggs, and some dogs shed eggs more frequently than others. The identification of these frequent shedders and the associated risk factors is an important cornerstone for constructing evidence-based deworming regimens. The purpose of this study is to identify risk factors associated with recurrence of periods of shedding Toxocara eggs in a cohort of household dogs older than six months. Methods: We performed a prospective study (July 2011 to October 2014) on shedding Toxocara eggs in a cohort of 938 household dogs older than six months from all over the Netherlands. The median follow-up time was 14 months. Monthly, owners sent faecal samples of their dogs for Toxocara testing and completed a questionnaire. Dogs were dewormed only after diagnosis of a patent infection (PI). Survival analysis was used to assess factors influencing the time to first diagnosed PIs (FPI) and the time to recurrent PIs (RPI). Results: The overall prevalence of PIs was 4.5 {\%}, resulting in an estimated average incidence of 0.54 PIs/dog/year. No PI was diagnosed in 67.9 {\%} of the dogs, 17.5 {\%} of the dogs went through only one PI and 14.6 {\%} had > 1 PI. Prevalence of PIs always peaked during wintertime. Increased hazards for first diagnosed PIs were associated with coprophagy, geophagy, walking off-leash for = 80 {\%} of walking time, reported worms in the faeces, feeding a commercial diet and suffering from urologic or respiratory conditions. Median time to reinfection was nine months. Factors associated with increased hazards for recurrent PIs were taking corticosteroids, changing dog's main purpose, and proxies for veterinary care-seeking behaviours. Conclusions: We concluded that targeted anthelmintic treatments in household dogs may be feasible as PIs tend to (re)occur in specific periods and in groups of dogs at high risk. Moreover, recurrent PIs appear to be influenced more by factors related to impaired immunity than environmental exposure to Toxocara eggs.",
keywords = "Deworming, Dogs, Longitudinal study, Recurrent patent infections, Toxocara canis",
author = "Rolf Nijsse and Lapo Mughini-Gras and Wagenaar, {Jaap A.} and Ploeger, {Harm W.}",
year = "2016",
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Recurrent patent infections with Toxocara canis in household dogs older than six months : a prospective study. / Nijsse, Rolf; Mughini-Gras, Lapo; Wagenaar, Jaap A.; Ploeger, Harm W.

In: Parasites & Vectors, Vol. 9, No. 1, 531, 2016.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Recurrent patent infections with Toxocara canis in household dogs older than six months

T2 - a prospective study

AU - Nijsse, Rolf

AU - Mughini-Gras, Lapo

AU - Wagenaar, Jaap A.

AU - Ploeger, Harm W.

PY - 2016

Y1 - 2016

N2 - Background: To reduce environmental contamination with Toxocara canis eggs, the current general advice is to deworm all dogs older than six months on average four times a year. However, only a small proportion of non-juvenile household dogs actually shed T. canis eggs, and some dogs shed eggs more frequently than others. The identification of these frequent shedders and the associated risk factors is an important cornerstone for constructing evidence-based deworming regimens. The purpose of this study is to identify risk factors associated with recurrence of periods of shedding Toxocara eggs in a cohort of household dogs older than six months. Methods: We performed a prospective study (July 2011 to October 2014) on shedding Toxocara eggs in a cohort of 938 household dogs older than six months from all over the Netherlands. The median follow-up time was 14 months. Monthly, owners sent faecal samples of their dogs for Toxocara testing and completed a questionnaire. Dogs were dewormed only after diagnosis of a patent infection (PI). Survival analysis was used to assess factors influencing the time to first diagnosed PIs (FPI) and the time to recurrent PIs (RPI). Results: The overall prevalence of PIs was 4.5 %, resulting in an estimated average incidence of 0.54 PIs/dog/year. No PI was diagnosed in 67.9 % of the dogs, 17.5 % of the dogs went through only one PI and 14.6 % had > 1 PI. Prevalence of PIs always peaked during wintertime. Increased hazards for first diagnosed PIs were associated with coprophagy, geophagy, walking off-leash for = 80 % of walking time, reported worms in the faeces, feeding a commercial diet and suffering from urologic or respiratory conditions. Median time to reinfection was nine months. Factors associated with increased hazards for recurrent PIs were taking corticosteroids, changing dog's main purpose, and proxies for veterinary care-seeking behaviours. Conclusions: We concluded that targeted anthelmintic treatments in household dogs may be feasible as PIs tend to (re)occur in specific periods and in groups of dogs at high risk. Moreover, recurrent PIs appear to be influenced more by factors related to impaired immunity than environmental exposure to Toxocara eggs.

AB - Background: To reduce environmental contamination with Toxocara canis eggs, the current general advice is to deworm all dogs older than six months on average four times a year. However, only a small proportion of non-juvenile household dogs actually shed T. canis eggs, and some dogs shed eggs more frequently than others. The identification of these frequent shedders and the associated risk factors is an important cornerstone for constructing evidence-based deworming regimens. The purpose of this study is to identify risk factors associated with recurrence of periods of shedding Toxocara eggs in a cohort of household dogs older than six months. Methods: We performed a prospective study (July 2011 to October 2014) on shedding Toxocara eggs in a cohort of 938 household dogs older than six months from all over the Netherlands. The median follow-up time was 14 months. Monthly, owners sent faecal samples of their dogs for Toxocara testing and completed a questionnaire. Dogs were dewormed only after diagnosis of a patent infection (PI). Survival analysis was used to assess factors influencing the time to first diagnosed PIs (FPI) and the time to recurrent PIs (RPI). Results: The overall prevalence of PIs was 4.5 %, resulting in an estimated average incidence of 0.54 PIs/dog/year. No PI was diagnosed in 67.9 % of the dogs, 17.5 % of the dogs went through only one PI and 14.6 % had > 1 PI. Prevalence of PIs always peaked during wintertime. Increased hazards for first diagnosed PIs were associated with coprophagy, geophagy, walking off-leash for = 80 % of walking time, reported worms in the faeces, feeding a commercial diet and suffering from urologic or respiratory conditions. Median time to reinfection was nine months. Factors associated with increased hazards for recurrent PIs were taking corticosteroids, changing dog's main purpose, and proxies for veterinary care-seeking behaviours. Conclusions: We concluded that targeted anthelmintic treatments in household dogs may be feasible as PIs tend to (re)occur in specific periods and in groups of dogs at high risk. Moreover, recurrent PIs appear to be influenced more by factors related to impaired immunity than environmental exposure to Toxocara eggs.

KW - Deworming

KW - Dogs

KW - Longitudinal study

KW - Recurrent patent infections

KW - Toxocara canis

U2 - 10.1186/s13071-016-1816-7

DO - 10.1186/s13071-016-1816-7

M3 - Article

VL - 9

JO - Parasites & Vectors

JF - Parasites & Vectors

SN - 1756-3305

IS - 1

M1 - 531

ER -