FAO - Brazilian Sub- Centers.

Report on agreement with

the VPRG and activities developed during 2004-05.

J.R.Martins

IPVDFwww.carrapatobovino.com

Sub-Center II

FMU – São Paulo

Coordinator: Gustavo Sabatini

Main Activity: In vitro tests aiming to show behaviour of 2 strains (Piquete e Guaratinguetá) with characteristic of

ivermectin resistance in the field.

Table 1. Results from the larval immersion tests (LIT), using commercial ivermectin (1%, injectable) in a 1% ethanol and 2% Triton X-100 solution, of field strains and susceptible control (“Porto Alegre” strain).

Sample N a Slope LC50 b (CL 95%) c (ppm)

Control 3 4.203 3.51 (3.04-4.06)

Pop 1 4 2.633 13.38 (10.12-22.41)

Pop 2 3 2.846 7.56 (5.90-10.68)

Pop 3 4 2.504 6.55 (5.63-7.88)

Pop 4 3 1.598 14.49 (9.40-36.79)

Pop 5 3 2.787 5.94 (4.80-7.80)

a N is the number of replicates of each test.b LC50 is the lethal concentration for 50%c CL is the confidence limits, given in brackets after the LC50.

Sub-CenterFMU - USP

Figure 1. Comparison of dose-mortality curves of field strains of Piquete, Sao Paulo, Brazil.

Sub-CenterFMU - SP

Figure 2. Comparison of dose-mortality curves of field strains of Guaratingueta, Sao Paulo, Brazil.

Sub-Center FMU - SP

Sub-Center I - IPVDF – RS

Coordinator: João Ricardo Martins

Main activities: *Stall tests in order to confirm suspect of ML resistance in the field; *Monitoring resistance to CE compounds; *Evaluate new acaricides/formulations *Extension activities

In 2005:

At least 2 strong field evidence of ivermectin resistance

-strain “São João”, municipality of Rio Pardo, RS

-strain “Bárbara”, municipality of São Jerônimo, RS

Sub-Center IPVDF – RS Coordinator: João Ricardo Martins

Common points:-no dip tank in the farm-intensive use of LM

Strain São João: (some aspects)

R to amitraz, SP, OP

S to mixtures (starting on july/2005)

Intensive use of generic LMs – 5 to 7 treatments a year, depending on animal category

*Calves are treated after born (1st day)

Strain is presently kept in the laboratory

Strain “Bárbara”

Use of mechanical aspersion

R to amitraz (jun/2005), SP & OP

S to mixtures (since jun/2005 in use)

All calves are treated after borning with LM and then, at 3-4 months, weaning, every changing of paddock,

*average 3 to 4 treatments a year, since 1995 (plus spray for horn-fly)

Test with tick larvae

Tests with larvae:

Characterization of strains and monitoring of resistance

Teste com larvas:

exposição as diferentes

concentrações

Teste de estábulo:

-boxes individuais para bovinos

Stall Test:

-calves remain in appropriate floor

for tick tick collection

Infestation: 250 mg of larvae

(5000 larvae)

Teste de estábulo:

Carrapatos são colhidos em peneiras com malha apropriada

RESULTS OF ADULT IMERSION TESTS

2005

Amitraz Mixture SP+ OP

Suscetible 12 (41,3%) 26 (92,8%)

Resistents 17 (58,6%) 02 (7,1%)

Total 29 28

Aspects of Amitraz resistance in Rio Grande do Sul:

-slow dissemination

-cases of reversibility

Amitraz

Resistance in

2005

FirstReport inRS: 1994

Sub-Center III –Embrapa/CNPGC

Coordinator – Renato Andreotti

Proposal of activities for the Sub-Centers in conjunction with the VPRG for 2006.

J/F/M A/M/J J/A/S O/N/D

Sub-Center IIPVDF/FEPAGRO

-Monitoring R & to establish a data bank1

-Maintenance & actualization of a “site” on cattle tick2 -Extension activities (talks, leaflets)3 -Maintenance of R reference strain4 >

-same-training course on diagnosis of tick R (in cooperation with Uruguay) -create a permanent virtual forum of discussion on tick control

-same -same-Technical meeting (?)

Sub-Center IIFMU/SP

-Monitoring R to LMs and to publish

-training course on

-Technical meeting (?)

Sub-Center IIIEmbrapa-CNPGC

-Hold a sub-center/VPRG meeting in order to discuss & planning activities

- -training course on

-Technical meeting (?)

*All subcenters should interact closely with the FAO Reference Center at CIVET Miguel Rubiño, Montevidéo, Uruguay (exchanging information, training courses, tick strains, impregnated papers, chemicals, etc.).