Revue scientifique et technique (International Office of Epizootics)
The use of insecticides is still the basic procedure for controlling most ectoparasites, but vari... more The use of insecticides is still the basic procedure for controlling most ectoparasites, but various methods are being developed to act in addition to, or in synergy with these products, so as to enhance the efficacy and reduce the adverse effects of insecticides, by contributing to ecologically acceptable strategies. These methods are classified as ecological control (modification of the environment of the parasite), biological control (predation, parasitism, action of pathogens, etc.), genetic control (release of sterile males, hybridisation, genetic manipulations) and mechanical control (insect traps, use of repellents). The application of such methods depends on the biological and ecological characteristics of the ectoparasite, and they may act directly or indirectly, affecting mortality and/or reproduction. The authors review the principal methods applicable to major groups of ectoparasites of veterinary interest. Non-chemical methods are the subject of wide-ranging and promisi...
Naive Beagle dogs (n = 5) were experimentally inoculated with two stocks of Babesia canis. Dogs w... more Naive Beagle dogs (n = 5) were experimentally inoculated with two stocks of Babesia canis. Dogs were examined regularly for parasitaemia and for antibodies, using the indirect immunofluorescent antibody test (IFAT). This test proved to be useful for the diagnosis of babesiosis. After primo-infection dogs seem to develop a certain degree of immunity, although this immunity is neither absolute nor of long duration. Treatment of infected dogs with imidocarb (6 mg/kg) cleared the infection, but did not prevent the production of IFAT-antibodies. An infected dog treated with long acting oxytetracycline (20 mg/kg) became a subclinical, chronic carrier of the disease.
The authors report on the results of experimental infections of teneral (age < 32 hours) and n... more The authors report on the results of experimental infections of teneral (age < 32 hours) and non-teneral (age between 80 and 96 hours) Glossina palpalis palpalis, G. p. gambiensis and G. morsitans morsitans with Trypanosoma congolense IL 1180. Flies were infected once on a parasitaemic rat. Teneral flies, both sexes indiscriminate, showed a procyclic and metacyclic infection rate respectively of 0.0588 and 0.7272 for G. p. palpalis; 0.0525 and 0.0416 for G. p. gambiensis; 0.6493 and 0.7300 for G. m. morsitans. Neither of the non-teneral G. palpalis subspecies had any vectorial competence, whereas G. m. morsitans had procyclic and metacyclic infection rates of 0.4541 and 0.7884. Statistical analysis could not demonstrate any significant difference in metacyclic infection rate between teneral and non-teneral G. m. morsitans. Teneral flies of each subspecies transmitted the infection to rats, used as hosts, before the twentieth day. Concerning trypanosome development in the fly, it ...
Fragmentation of tsetse habitat in eastern Zambia is largely due to encroachments by subsistence ... more Fragmentation of tsetse habitat in eastern Zambia is largely due to encroachments by subsistence farmers into new areas in search of new agricultural land. The impact of habitat fragmentation on tsetse populations is not clearly understood. This study was aimed at establishing the impact of habitat fragmentation on physiological and demographic parameters of tsetse flies in order to enhance the understanding of the relationship between fragmentation and African animal trypanosomosis (AAT) risk. A longitudinal study was conducted to establish the age structure, abundance, proportion of females and trypanosome infection rate of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) in areas of varying degrees of habitat fragmentation in Eastern Zambia. Black screen fly rounds were used to sample tsetse populations monthly for 1 year. Logistic regression was used to analyse age, proportion of females and infection rate data. Flies got significantly older as fragmentation increase...
In an effort to understand better the transmission risk as well for the animal African trypanosom... more In an effort to understand better the transmission risk as well for the animal African trypanosomosis (AAT) as for the human trypanosomosis (HAT) in the peri-urban zone of Kinshasa, a serologic study was carried out in local pig farms from 2003 to 2005. An indirect ELISA was used to detect the presence of trypanosome antibodies in 1,240 pigs originating from 404 farms. Seropositivity was recorded in 155 farms (38%), but varied considerably according to the district. In 6% of the farms TAA could be confirmed by parasitological examination. Trapping sites (n = 367) established in the neighbourhood of pig farms made it possible to capture 1,935 tsetse flies (Glossina fuscipes quanzensis). Among 562 dissected flies 23 were found to harbour trypanosomes resulting in an infection rate of 4.1%. In the majority of the districts the transmission risk for animal trypanosomosis anticipated from the apparent vector densities was corroborated by the serology. Zones with strong indications of loc...
Tsetse-transmitted human or livestock trypanosomiasis is one of the major constraints to rural de... more Tsetse-transmitted human or livestock trypanosomiasis is one of the major constraints to rural development in sub-Saharan Africa. The epidemiology of the disease is determined largely by tsetse fly density. A major factor, contributing to tsetse population density is the availability of suitable habitat. In large parts of Africa, encroachment of people and their livestock resulted in a destruction and fragmentation of such suitable habitat. To determine the effect of habitat change on tsetse density a study was initiated in a tsetse-infested zone of eastern Zambia. The study area represents a gradient of habitat change, starting from a zone with high levels of habitat destruction and ending in an area where livestock and people are almost absent. To determine the distribution and density of the fly, tsetse surveys were conducted throughout the study area in the dry and in the rainy season. Landsat ETM+ imagery covering the study area were classified into four land cover classes (mun...
In 2011, Culicoides (Diptera: Ceratopogonidae) were collected at 16 locations covering four regio... more In 2011, Culicoides (Diptera: Ceratopogonidae) were collected at 16 locations covering four regions of Belgium with Onderstepoort Veterinary Institute (OVI) traps and at two locations with Rothamsted suction traps (RSTs). Quantification of the collections and morphological identification showed important variations in abundance and species diversity between individual collection sites, even for sites located in the same region. However, consistently higher numbers of Culicoides midges were collected at some sites compared with others. When species abundance and diversity were analysed at regional level, between-site variation disappeared. Overall, species belonging to the subgenus Avaritia together with Culicoides pulicaris (subgenus Culicoides) were the most abundant, accounting for 80% and 96% of all midges collected with RSTs and OVI traps, respectively. Culicoides were present during most of the year, with Culicoides obsoletus complex midges found from 9 February until 27 Decemb...
African Animal Trypanosomosis is threatening the agricultural production and cattle breeding more... more African Animal Trypanosomosis is threatening the agricultural production and cattle breeding more severely than any other livestock disease in the continent, even more since the advent of drug resistance. A longitudinal study was conducted from November 2012 to May 2013 in the Ghibe valley to evaluate diminazene aceturate (DA) resistance and assess livestock owner's perception of trypanocidal drug use. Four Peasant Associations (PAs) were purposively selected and the cattle randomly sampled in each PAs. At the beginning of the study (t0), 106 bovines positive for trypanosomes by the haematocrit centrifugation technique (HCT) and 119 negative control animals were recruited for six months follow-up using HCT, 18S-PCR-RFLP, DpnII-PCR-RFLP and microsatellite analysis. Prevalence of trypanosomosis was 18.1% based on the HCT technique and the mean PCV value was 23.6±5.1% for the 587 sampled cattle. Out of the 106 HCT positive, 64 (60.4%) were positive for the presence of trypanosomes ...
Revue scientifique et technique (International Office of Epizootics), 2004
A survey was conducted by questionnaire to assess the current undergraduate curricula in the vete... more A survey was conducted by questionnaire to assess the current undergraduate curricula in the veterinary faculties of sub-Saharan Africa. The survey also examined how such curricula are adjusted for crucial developments in the veterinary field, such as privatisation, decentralisation and globalisation, with the increasing risk of transboundary diseases. The results demonstrate that most of these faculties face serious shortages, both in their budgets and of qualified personnel. Most faculties do not have formal feedback systems to allow former graduates to contribute to periodic reviews of the curricula. Although some north-south and south-south collaboration exists among African veterinary faculties, more intensive regional collaboration at both undergraduate and postgraduate level would allow optimal use of the available funds and human resources. The creation of a regional veterinary council and a committee of deans would be an excellent step forward in ensuring internationalisati...
The prophylactic activity of a subcutaneously implanted slow release device, containing homidium ... more The prophylactic activity of a subcutaneously implanted slow release device, containing homidium bromide, was assessed in rabbits, challenged with different stocks of T. congolense, and compared with the classical treatment of 1 mg homidium bromide/kg b.w. intramuscularly. The prophylactic activity of the intramuscular injection was less than a month, while the slow release device protected the rabbits against seven challenges with T. congolense during a period of more than 300 days.
An experiment was set up to assess the influence of some parameters on the production of ascites ... more An experiment was set up to assess the influence of some parameters on the production of ascites and monoclonal antibodies against circulating excretory-secretory antigens of Taenia saginata cysticerci in mice. The following parameters were examined: time lapse between priming and the inoculation of hybridoma cells, age and body weight of the mice at the time of inoculation, number of cells injected IP, and the resulting antibody titers of the ascites. In this experiment the method used to prime the mice was the only factor having an influence on the amount of ascites produced. Injection of a higher number of hybridoma cells (2-4 x 10(6) cells) coincided with higher antibody titers and resulted in an earlier ascites production. The antibody titer of the ascites was increasing with time.
Revue scientifique et technique (International Office of Epizootics)
The use of insecticides is still the basic procedure for controlling most ectoparasites, but vari... more The use of insecticides is still the basic procedure for controlling most ectoparasites, but various methods are being developed to act in addition to, or in synergy with these products, so as to enhance the efficacy and reduce the adverse effects of insecticides, by contributing to ecologically acceptable strategies. These methods are classified as ecological control (modification of the environment of the parasite), biological control (predation, parasitism, action of pathogens, etc.), genetic control (release of sterile males, hybridisation, genetic manipulations) and mechanical control (insect traps, use of repellents). The application of such methods depends on the biological and ecological characteristics of the ectoparasite, and they may act directly or indirectly, affecting mortality and/or reproduction. The authors review the principal methods applicable to major groups of ectoparasites of veterinary interest. Non-chemical methods are the subject of wide-ranging and promisi...
Naive Beagle dogs (n = 5) were experimentally inoculated with two stocks of Babesia canis. Dogs w... more Naive Beagle dogs (n = 5) were experimentally inoculated with two stocks of Babesia canis. Dogs were examined regularly for parasitaemia and for antibodies, using the indirect immunofluorescent antibody test (IFAT). This test proved to be useful for the diagnosis of babesiosis. After primo-infection dogs seem to develop a certain degree of immunity, although this immunity is neither absolute nor of long duration. Treatment of infected dogs with imidocarb (6 mg/kg) cleared the infection, but did not prevent the production of IFAT-antibodies. An infected dog treated with long acting oxytetracycline (20 mg/kg) became a subclinical, chronic carrier of the disease.
The authors report on the results of experimental infections of teneral (age < 32 hours) and n... more The authors report on the results of experimental infections of teneral (age < 32 hours) and non-teneral (age between 80 and 96 hours) Glossina palpalis palpalis, G. p. gambiensis and G. morsitans morsitans with Trypanosoma congolense IL 1180. Flies were infected once on a parasitaemic rat. Teneral flies, both sexes indiscriminate, showed a procyclic and metacyclic infection rate respectively of 0.0588 and 0.7272 for G. p. palpalis; 0.0525 and 0.0416 for G. p. gambiensis; 0.6493 and 0.7300 for G. m. morsitans. Neither of the non-teneral G. palpalis subspecies had any vectorial competence, whereas G. m. morsitans had procyclic and metacyclic infection rates of 0.4541 and 0.7884. Statistical analysis could not demonstrate any significant difference in metacyclic infection rate between teneral and non-teneral G. m. morsitans. Teneral flies of each subspecies transmitted the infection to rats, used as hosts, before the twentieth day. Concerning trypanosome development in the fly, it ...
Fragmentation of tsetse habitat in eastern Zambia is largely due to encroachments by subsistence ... more Fragmentation of tsetse habitat in eastern Zambia is largely due to encroachments by subsistence farmers into new areas in search of new agricultural land. The impact of habitat fragmentation on tsetse populations is not clearly understood. This study was aimed at establishing the impact of habitat fragmentation on physiological and demographic parameters of tsetse flies in order to enhance the understanding of the relationship between fragmentation and African animal trypanosomosis (AAT) risk. A longitudinal study was conducted to establish the age structure, abundance, proportion of females and trypanosome infection rate of Glossina morsitans morsitans Westwood (Diptera: Glossinidae) in areas of varying degrees of habitat fragmentation in Eastern Zambia. Black screen fly rounds were used to sample tsetse populations monthly for 1 year. Logistic regression was used to analyse age, proportion of females and infection rate data. Flies got significantly older as fragmentation increase...
In an effort to understand better the transmission risk as well for the animal African trypanosom... more In an effort to understand better the transmission risk as well for the animal African trypanosomosis (AAT) as for the human trypanosomosis (HAT) in the peri-urban zone of Kinshasa, a serologic study was carried out in local pig farms from 2003 to 2005. An indirect ELISA was used to detect the presence of trypanosome antibodies in 1,240 pigs originating from 404 farms. Seropositivity was recorded in 155 farms (38%), but varied considerably according to the district. In 6% of the farms TAA could be confirmed by parasitological examination. Trapping sites (n = 367) established in the neighbourhood of pig farms made it possible to capture 1,935 tsetse flies (Glossina fuscipes quanzensis). Among 562 dissected flies 23 were found to harbour trypanosomes resulting in an infection rate of 4.1%. In the majority of the districts the transmission risk for animal trypanosomosis anticipated from the apparent vector densities was corroborated by the serology. Zones with strong indications of loc...
Tsetse-transmitted human or livestock trypanosomiasis is one of the major constraints to rural de... more Tsetse-transmitted human or livestock trypanosomiasis is one of the major constraints to rural development in sub-Saharan Africa. The epidemiology of the disease is determined largely by tsetse fly density. A major factor, contributing to tsetse population density is the availability of suitable habitat. In large parts of Africa, encroachment of people and their livestock resulted in a destruction and fragmentation of such suitable habitat. To determine the effect of habitat change on tsetse density a study was initiated in a tsetse-infested zone of eastern Zambia. The study area represents a gradient of habitat change, starting from a zone with high levels of habitat destruction and ending in an area where livestock and people are almost absent. To determine the distribution and density of the fly, tsetse surveys were conducted throughout the study area in the dry and in the rainy season. Landsat ETM+ imagery covering the study area were classified into four land cover classes (mun...
In 2011, Culicoides (Diptera: Ceratopogonidae) were collected at 16 locations covering four regio... more In 2011, Culicoides (Diptera: Ceratopogonidae) were collected at 16 locations covering four regions of Belgium with Onderstepoort Veterinary Institute (OVI) traps and at two locations with Rothamsted suction traps (RSTs). Quantification of the collections and morphological identification showed important variations in abundance and species diversity between individual collection sites, even for sites located in the same region. However, consistently higher numbers of Culicoides midges were collected at some sites compared with others. When species abundance and diversity were analysed at regional level, between-site variation disappeared. Overall, species belonging to the subgenus Avaritia together with Culicoides pulicaris (subgenus Culicoides) were the most abundant, accounting for 80% and 96% of all midges collected with RSTs and OVI traps, respectively. Culicoides were present during most of the year, with Culicoides obsoletus complex midges found from 9 February until 27 Decemb...
African Animal Trypanosomosis is threatening the agricultural production and cattle breeding more... more African Animal Trypanosomosis is threatening the agricultural production and cattle breeding more severely than any other livestock disease in the continent, even more since the advent of drug resistance. A longitudinal study was conducted from November 2012 to May 2013 in the Ghibe valley to evaluate diminazene aceturate (DA) resistance and assess livestock owner's perception of trypanocidal drug use. Four Peasant Associations (PAs) were purposively selected and the cattle randomly sampled in each PAs. At the beginning of the study (t0), 106 bovines positive for trypanosomes by the haematocrit centrifugation technique (HCT) and 119 negative control animals were recruited for six months follow-up using HCT, 18S-PCR-RFLP, DpnII-PCR-RFLP and microsatellite analysis. Prevalence of trypanosomosis was 18.1% based on the HCT technique and the mean PCV value was 23.6±5.1% for the 587 sampled cattle. Out of the 106 HCT positive, 64 (60.4%) were positive for the presence of trypanosomes ...
Revue scientifique et technique (International Office of Epizootics), 2004
A survey was conducted by questionnaire to assess the current undergraduate curricula in the vete... more A survey was conducted by questionnaire to assess the current undergraduate curricula in the veterinary faculties of sub-Saharan Africa. The survey also examined how such curricula are adjusted for crucial developments in the veterinary field, such as privatisation, decentralisation and globalisation, with the increasing risk of transboundary diseases. The results demonstrate that most of these faculties face serious shortages, both in their budgets and of qualified personnel. Most faculties do not have formal feedback systems to allow former graduates to contribute to periodic reviews of the curricula. Although some north-south and south-south collaboration exists among African veterinary faculties, more intensive regional collaboration at both undergraduate and postgraduate level would allow optimal use of the available funds and human resources. The creation of a regional veterinary council and a committee of deans would be an excellent step forward in ensuring internationalisati...
The prophylactic activity of a subcutaneously implanted slow release device, containing homidium ... more The prophylactic activity of a subcutaneously implanted slow release device, containing homidium bromide, was assessed in rabbits, challenged with different stocks of T. congolense, and compared with the classical treatment of 1 mg homidium bromide/kg b.w. intramuscularly. The prophylactic activity of the intramuscular injection was less than a month, while the slow release device protected the rabbits against seven challenges with T. congolense during a period of more than 300 days.
An experiment was set up to assess the influence of some parameters on the production of ascites ... more An experiment was set up to assess the influence of some parameters on the production of ascites and monoclonal antibodies against circulating excretory-secretory antigens of Taenia saginata cysticerci in mice. The following parameters were examined: time lapse between priming and the inoculation of hybridoma cells, age and body weight of the mice at the time of inoculation, number of cells injected IP, and the resulting antibody titers of the ascites. In this experiment the method used to prime the mice was the only factor having an influence on the amount of ascites produced. Injection of a higher number of hybridoma cells (2-4 x 10(6) cells) coincided with higher antibody titers and resulted in an earlier ascites production. The antibody titer of the ascites was increasing with time.
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Papers by Reginald De Deken