Approaches towards tick and tick-borne diseases control

Ticks are obligate haematophagous ectoparasites of wild and domestic animals as well as humans, considered to be second worldwide to mosquitoes as vectors of human diseases. Tick-borne diseases are responsible worldwide for great economic losses in terms of mortality and morbidity of livestock animals. This review concerns to the different tick and tick-parasites control methods having a major focus on vaccines. Control of tick infestations has been mainly based on the use of acaricides, a control measure with serious drawbacks, as responsible for the contamination of milk and meat products, as a selective factor for acaricide-resistant ticks and as an environmental contaminant. Research on alternatives to the use of acaricides is strongly represented by tick vaccines considered a more cost-effective and environmentally safe strategy. Vaccines based on the Bm86 tick antigen were used in the first commercially available cattle tick vaccines and showed good results in reducing tick numbers, affecting weight and reproductive performance of female ticks which resulted in reduction of cattle tick populations over time and consequently lower reduction of the pathogen agents they carry

In vitro studies of the levels of resistance to drugs of Plasmodium falciparum, from 1983 to 1986

Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Biomedical Research Institute. Maryland, USA.Foram realizados 171 testes de sensibilidade (microtécnica) com cepas de Plasmodium falciparum da Região Amazônica brasileira para cloroquina, mefloquina, amodiaquina e quinino. Os testes tiveram duração de 24 horas com as drogas preparadas na hora da realização de cada teste. Os resultados mostraram elevada resistência a cloroquina (83%) e sensibilidade em quase a totalidade das amostras testadas para mefloquina (97,7%). Para amodiaquina e quinino observou-se sensibilidade em 51,0% e 56,5% das cepas, respectivamente. Este estudo demonstra a emergência de um possível foco de resistência do Plasmodium falciparum a mefloquina, em Tucuruí.Drug resistance tests were performed with 171 strains of P. falciparum obtained from the Amazon Region, using chloroquine, mefloquine, amodiaquine and quinine. Tests lasted about 24 hours and the drug solutions were prepared just before use. Results show high percentage of resistance to chloroquine (83%) whereas nearly all strains were shown to be sensitive to mefloquine (97.7%). For both amodiaquine and quinine sensitivities were of 51.0% and 56.5% respectively. The present study demonstrates that resistance to mefloquine may be starting in Tucuruí, Pará

Characterization of Plasmodium falciparum strains of the State Rondônia Brazil, using microtests sensitivity to antimalarials microtechniques, enzymatic typing and monoclonal antibodies

Secretaria de Estado da Saúde. Superintendência de Controle de Endemias. Laboratório de Malária. São Paulo, SP, Brasil.Secretaria de Estado da Saúde. Superintendência de Controle de Endemias. Laboratório de Malária. São Paulo, SP, Brasil.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.Blomedlcal Research Institute. Maryland, USA.Nove amostras de Plasmodium falciparum foram coletadas de migrantes infectados no Estado de Rondônia. Estas amostras foram mantidas em cultivo para caracterização por tipificação por enzimática em acetato de celulose, sensibilidade a cloroquina, amodiaquina, mefloquina e quinino e análise da diversidade antigênica através de anticorpos monoclonais específicos. Os resultados obtidos mostraram variação entre todas as amostras estudadas: encontrou-se resistência crescente a cloroquina, resistência intermediaria a amodiaquina e quinino e sensibilidade a baixos níveis de mefloquina; apenas dois isolados mostraram sensibilidade a todas as drogas. A tipificação enzimática mostrou presença de parasitas GPI 1 e 2 e ADA 1 e 2, enquanto que para PEP e LDH todas as amostras foram do tipo 1. Sorotipagem com anticorpos monoclonais PSA mostrou presencia de três sorotipos diferentes (II, III E IV). Estes resultados mostraram: a) variação entre as amostras para os marcadores analisados; b) nesta região, para o pequeno numero de amostras analisadas, não foram observadas diferenças significativas ou novos tipos de parasitas.Nine samples of Plasmodium falciparum were collected from migrant workers who were infected in the State of Rondônia, Brazil. These samples were maintained in culture for characterlzation by enzyme typing using acetate cellulose electrophoresis, drug susceptlbility to chioroquine, amodiaquine, mefloquine and quinnine and antigenic diversity analysis using strain specific monoclonal antibodies. The results obtained have confirmed major variation among alI samples studied: it was found consistent resistance to chloroquine moderated resistance to amodiaquine and quinine and susceptibllity to low levels of mefloquine; only two isolates have shown susceptibility to alI drugs in the in vitre assays. Enzyme typing showed presence of both GPI 1 and 2 and ADA 1 and 2 parasites, while for PEP and LDR alI samples were type 1. Serotyping with PSA monoclonal antibodies show. ed presence of three different serotypes (lI, III and IV). These results confirm: a) variation among samples for markers analysed; b) In this area and for the small number of samples studied, no significant differences or new types of parasites were seen