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Table 1 Model parameters and sources, as used in the model. Parameter means are shown in Table 3

From: Environmental contamination with Toxocara eggs: a quantitative approach to estimate the relative contributions of dogs, cats and foxes, and to assess the efficacy of advised interventions in dogs

Parameter

Description

Estimation

Source

Dogs

   

   D 1jz

Density of dogs of age group j in area z

Data

[20]

   P 1jz

Prevalence of Toxocara patent infection in dogs of age group j in area z

= p 1jz  × c 1jz

See below

   p 1jz

Coprological prevalence of Toxocara egg shedding dogs of age group j in area z

~Beta (a 1jz  + 1, b 1jz  + 1), where: a 1,1,1 = 2, b 1,1,1 = 47; a 1,2,1 = 5, b 1,2,1 = 129; a 1,1,2 = 10, b 1,1,2 = 122; a 1,2,2 = 12, b 1,2,2 = 389; a 1,1,3 = 6, b 1,1,3 = 43; a 1,2,3 = 7, b 1,2,3 = 137

[9]

   c 1jz

Proportion of dogs of age group j in area z that do not display a coprophagic behaviour

~Beta (a 1jz  + 1, b 1jz  + 1), where: a 1,1,1 = 26, b 1,1,1 = 22; a 1,2,1 = 80, b 1,2,1 = 54; a 1,1,2 = 56, b 1,1,2 = 75; a 1,2,2 = 226, b 1,2,2 = 175; a 1,1,3 = 29, b 1,1,3 = 18; a 1,2,3 = 89, b 1,2,3 = 55

[9]

   F 1jz

Average faecal output of a dog of age group j released daily into the environment of area z

= f 1 × s 1jz

See below

   f 1

Average faecal output of a dog

~Pert (21, 254, 1074)

[22–33]

   s 1jz

Proportion of dog owners that do not comply to dog waste clean-up policies for dogs of age group j in area z

~Beta (a 1jz  + 1, b 1jz  + 1), where: a 1,1,1 = 20, b 1,1,1 = 28; a 1,2,1 = 80, b 1,2,1 = 54; a 1,1,2 = 87, b 1,1,2 = 44; a 1,2,2 = 277, b 1,2,2 = 154; a 1,1,3 = 27, b 1,1,3 = 20; a 1,2,3 = 106, b 1,2,3 = 37

[9]

   I 1j

Infection intensity (EPG) for dogs of age group j

I 1,1 ~ Poisson (341.2); I 1,2 ~ Poisson (163.7)

[34]

Household cats

   

   D 2jz

Density of household cats of age group j in area z

Data

[20]

   P 2jz

Prevalence of Toxocara patent infection in household cats of age group j in area z

~Beta (a 2jz  + 1, b 2jz  + 1), where: a 2,1,1 = 0, b 2,1,1 = 2; a 2,2,1 = 0, b 2,2,1 = 18; a 2,1,2 = 2, b 2,1,2 = 15; a 2,2,2 = 8, b 2,2,2 = 52; a 2,1,3 = 2, b 2,1,3 = 1; a 2,2,3 = 5, b 2,2,3 = 12

[Nijsse, unpublished data]

   F 2jz

Average faecal output of a household cat of age group j released daily into the environment of area z

= f 2 × o 2jz

See below

   f 2

Average faecal output of a household cat

~Pert (10.2, 19.4, 52.4)

[35–39]

   o 2jz

Proportion of household cats of group j in area z with outdoor access

~Beta (a 2jz  + 1, b 2jz  + 1), where: a 2,1,1 = 1, b 2,1,1 = 1; a 2,2,1 = 5, b 2,2,1 = 13; a 2,1,2 = 3, b 2,1,2 = 13; a 2,2,2 = 45, b 2,2,2 = 13; a 2,1,3 = 2, b 2,1,3 = 1; a 2,2,3 = 14, b 2,2,3 = 3

[Nijsse, unpublished data]

   I 2j

Infection intensity (EPG) for household cats of age group j

I 2,1 ~ Poisson (372.8); I 2,2 ~ Poisson (81.7)

[40]

Stray cats

   

   D 3jz

Density of stray cats of age group j in area z

~Pert (135,000,667,500,1,200,000) × D 2jz  /(∑ j  ∑ i   D 2jz )

Personal communication: preliminary estimate of feral cat project WUR Wageningen

   P 3j

Prevalence of Toxocara patent infection in stray cats of age group j

~Beta (a 3jz  + 1, b 3jz  + 1), where: a 3,1,1 = 16, b 3,1,1 = 12; a 3,2,1 = 17, b 3,2,1 = 8; a 3,1,2 = 16, b 3,1,2 = 12; a 3,2,2 = 17, b 3,2,2 = 8; a 3,1,3 = 16, b 3,1,3 = 12; a 3,2,3 = 17, b 3,2,3 = 8

[11]

   F 3

Average faecal output of a stray cat

~Pert (10.2, 19.4, 52.4)

[35–39]

   I 3j

Infection intensity (EPG) for stray cats of age group j

I 3,1 ~ Poisson (372.8); I 3,2 ~ Poisson (81.7)

[40]

Foxes

   

   D 4jz

Density of foxes of age group j in area z

~Pert (0.5, 2.25, 4) × d 4jz /(∑ j ∑ i d 4jz )

[41]

   d 4jz

Total number of foxes of age group j shot in area z

Data

[41]

   P 4jz

Prevalence of Toxocara patent infection in foxes of age group j in area z

~Beta (a 4jz  + 1, b 4jz  + 1), where: a 4,1,1 = 1, b 4,1,1 = 1; a 4,2,1 = 1, b 4,2,1 = 1; a 4,1,2 = 18, b 4,1,2 = 28; a 4,2,2 = 9, b 4,2,2 = 12; a 4,1,3 = 57, b 4,1,3 = 74; a 4,2,3 = 19, b 4,2,3 = 39

[41]

   F 4

Average faecal output of a fox

Log(F 4) ~ Normal (95, 18)

[42]

   I 4j

Infection intensity (EPG) for foxes of age group j

I 4,1 ~ Poisson (157); I 4,2 ~ Poisson (366)

[12]

  1. Description, estimation and data sources of the model parameters used to quantify the number of Toxocara eggs released into the environment by non-juvenile (≥6 month-old) dogs, household cats, stray cats and foxes in the Netherlands. Parameter means are shown in Table 3
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Parasites & Vectors

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