RESUMO
OBJECTIVE: The aim of this study was to assess health changes seen in routine homeopathic care for patients with a wide range of chronic conditions who were referred to a hospital outpatient department. DESIGN: This was an observational study of 6544 consecutive follow-up patients during a 6-year period. SETTING: Hospital outpatient unit within an acute National Health Service (NHS) Teaching Trust in the United Kingdom. PARTICIPANTS: Every patient attending the hospital outpatient unit for a follow-up appointment over the study period was included, commencing with their first follow-up attendance. MAIN OUTCOME MEASURE: Outcomes were based on scores on a 7-point Likert-type scale at the end of the consultation and were assessed as overall outcomes compared to the initial baseline assessments. RESULTS: A total of 6544 consecutive follow-up patients were given outcome scores. Of the patients 70.7% (n = 4627) reported positive health changes, with 50.7% (n = 3318) recording their improvement as better (+2) or much better (+3). CONCLUSIONS: Homeopathic intervention offered positive health changes to a substantial proportion of a large cohort of patients with a wide range of chronic diseases. Additional observational research, including studies using different designs, is necessary for further research development in homeopathy.
Assuntos
Doença Crônica/epidemiologia , Doença Crônica/terapia , Homeopatia/estatística & dados numéricos , Ambulatório Hospitalar/estatística & dados numéricos , Satisfação do Paciente/estatística & dados numéricos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Nível de Saúde , Homeopatia/métodos , Humanos , Masculino , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde/estatística & dados numéricos , Inquéritos e Questionários , Reino Unido/epidemiologiaRESUMO
The persistence of Anaplasma marginale Theiler in male Dermacentor andersoni Stiles ticks exposed to the organism as adults was studied as the ticks were successively transferred to five susceptible calves. All calves fed upon by these ticks rapidly developed clinical anaplasmosis; incubation periods of infection ranged from 19 to 26 d and did not change significantly with successive feedings. Development of A. marginale in tick midgut and salivary glands was followed daily during tick feeding (total, 35 d) with light microscopy and DNA hybridization. With microscopy, A. marginale colonies persisted in midgut cells throughout the experiment. Large colonies were observed in gut muscle cells on days 8 through 35 and were the predominant infected cell type during this part of feeding. Colonies were seen in salivary gland acini from day 2 throughout the 35-d experiment. The DNA probe confirmed the presence of Anaplasma DNA in midgut and salivary glands throughout the experiment. Quantitative estimates of infection intensity in tissues of individual ticks approximated 10(7) initial body equivalents, confirming heavy infections. A marginale in midgut tissues decreased with feeding time, whereas the estimated number of organisms in salivary glands remained constant. These data demonstrate that D. andersoni males are efficient vectors of A. marginale and may be potential reservoirs of infection for ruminants for extended periods.
Assuntos
Anaplasma/isolamento & purificação , Anaplasmose/transmissão , Vetores Aracnídeos/microbiologia , Doenças dos Bovinos/transmissão , Dermacentor/microbiologia , Anaplasma/genética , Animais , Bovinos , DNA Bacteriano/análise , Masculino , Hibridização de Ácido NucleicoRESUMO
Distribution of erythromycin into subcutaneous tissue chambers was characterised pharmacokinetically and the effect of Pasteurella haemolytica infection on the extent of penetration was studied. Thermoplastic tissue chambers were implanted subcutaneously in the paralumbar fossae of six calves. Thirty-five days after implantation, the tissue chamber distribution of intramuscularly administered erythromycin (30 mg kg-1) was studied. Chambers were then inoculated with P haemolytica and the tissue chamber pharmacokinetics of erythromycin were again studied. Diffusion of erythromycin into tissue chambers was best described using a two-compartment model with tissue chambers representing a relatively inaccessible compartment. Despite changes in chamber fluid pH, the extent of erythromycin penetration into chambers was not affected by P haemolytica inoculation. Comparison of computer simulated concentration-time curves resulting from different routes of administration revealed that penetration of erythromycin into less accessible sites was more likely to be higher after intravenous administration than after intramuscular administration.
Assuntos
Eritromicina/farmacocinética , Mannheimia haemolytica , Infecções por Pasteurella/metabolismo , Animais , Bovinos , Eritromicina/administração & dosagem , Eritromicina/toxicidade , Injeções Intramusculares , Mannheimia haemolytica/efeitos dos fármacos , Modelos Biológicos , Infecções por Pasteurella/sangue , Pele/metabolismo , Fatores de Tempo , Distribuição TecidualRESUMO
A double L-shaped intestinal cannula was developed in an attempt to overcome problems observed previously with simple T-type cannulas. The cannula was constructed from cyclopolyvinyl chloride water pipe fittings. Construction materials were fairly rigid, but by connecting the split cannula pieces with elastic castration bands the cannula had some flexibility. Placing a short cone over the exposed cannula barrel reduced mechanical damage to the intestine. The double L cannula required a much smaller incision in the intestine during surgical insertion than a T-type cannula; it also simplified replacement. Construction is described; use and performance of the cannula has been satisfactory.
Assuntos
Cateterismo/veterinária , Bovinos/cirurgia , Digestão , Intestinos/cirurgia , Animais , Bovinos/fisiologia , Duodeno/fisiologia , Duodeno/cirurgia , Ingestão de Alimentos , Feminino , Íleo/fisiologia , Íleo/cirurgia , Intestinos/fisiologia , Masculino , Manejo de Espécimes/veterinária , Aumento de PesoRESUMO
A subcutaneous soft tissue infection model in calves was used to study the in vivo response of Pasteurella haemolytica to erythromycin and dexamethasone. Two tissue chambers were implanted SC in each of 12 calves. At 45 days after implantation, all tissue chambers were inoculated with an erythromycin-sensitive strain of P haemolytica. Starting 24 hours after inoculation, calves were allotted to 4 groups of equal size and a 2 x 2-factorial arrangement of treatments was applied: 3 calves were given erythromycin (30 mg/kg of body weight, IM, for 5 days), 3 calves were given dexamethasone (0.05 mg/kg, IM, for 2 days), 3 calves were given erythromycin and dexamethasone, and the remaining calves served as nontreated controls. Chamber fluids were tested daily, and the response to treatment was measured. Neither erythromycin nor dexamethasone affected viability or growth of bacteria within tissue chambers. Dexamethasone had no effect on the influx of neutrophils into infected chambers. Despite repeated administration of a high dose of erythromycin and attainment of adequate concentration in serum, erythromycin concentration in chamber fluids did not exceed the minimal inhibitory concentration established in vitro. These results indicate that the clinical efficacy of erythromycin against P haemolytica sequestered in consolidated pneumonic lesions may not be well correlated with predictions based on serum pharmacokinetic and in vitro susceptibility data.
Assuntos
Doenças dos Bovinos/tratamento farmacológico , Dexametasona/uso terapêutico , Eritromicina/uso terapêutico , Mannheimia haemolytica/efeitos dos fármacos , Infecções por Pasteurella/veterinária , Albuminas/análise , Animais , Bovinos , Dexametasona/administração & dosagem , Dexametasona/farmacocinética , Cultura em Câmaras de Difusão , Modelos Animais de Doenças , Quimioterapia Combinada , Eritromicina/administração & dosagem , Eritromicina/farmacocinética , Concentração de Íons de Hidrogênio , Injeções Intramusculares/veterinária , Contagem de Leucócitos/veterinária , Neutrófilos , Infecções por Pasteurella/tratamento farmacológico , Distribuição TecidualRESUMO
Four splenectomized dairy calves were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source (donor) for laboratory-reared Dermacentor andersoni Stiles nymphs. Two donor calves developed higher parasitemias during tick feeding than did the 2 other donor calves. One month after molting, adult ticks were incubated at 37 C for 2.5 days to stimulate development of colonies of A marginale, and homogenates of gut were made from ticks fed on each donor calf. Eight susceptible, splenectomized dairy calves (2 per donor calf) were each inoculated IV with the gut homogenates collected from 50 adult ticks and were monitored for patent A marginale infection. Gut tissues from these same groups of ticks were processed for histologic studies. Homogenates from ticks infected on donor calves with lower parasitemias caused infections with longer prepatent periods (av, 43.25 days) than did similar homogenates made from ticks infected by feeding on donor calves with higher parasitemias (av, 31.0 days). Also, sections of gut tissues from ticks infected at the lower parasitemias contained fewer (av, 0.65) colonies/0.001 mm2 of tissue examined than did those from ticks infected at higher parasitemias (av, 6.31).
Assuntos
Anaplasma/crescimento & desenvolvimento , Anaplasmose/microbiologia , Vetores Artrópodes/microbiologia , Doenças dos Bovinos/microbiologia , Dermacentor/microbiologia , Sepse/veterinária , Carrapatos/microbiologia , Anaplasmose/transmissão , Animais , Bovinos , Doenças dos Bovinos/transmissão , Feminino , Masculino , Sepse/microbiologia , Sepse/transmissãoRESUMO
Colonies of Anaplasma marginale Theiler were studied in midgut epithelial cells of nymphal Dermacentor andersoni Stiles that had become infected by feeding on splenectomized calves with anaplasmosis. Colonies of A marginale were not observed in nymphal ticks killed during the 6-day feeding period, but were present in sections of midgut epithelial cells of ticks killed as early as 5 days after repletion. Colonies of A marginale also were present in ticks examined throughout development to the adult stage. Two distinct morphologic types of colonies were observed and categorized by light microscopy as nymphal types 1 and 2. Colonies that were morphologically indistinct with characteristics common in both types were termed transitional nymphal (TsN) colonies. Nymphal type 1 (Ny1) colonies were observed at 5 days after repletion and nymphal type 2 (Ny2) colonies were first observed at 20 days after feeding. Representatives of each colony type were selected by light microscopy and were sectioned for electron microscopy. The Ny1 contained small particles and large, round reticulated forms, some of which appeared to be dividing by binary fission. The Ny2 also contained reticulated organisms, but they were rod-like in shape, and there was no morphologic evidence of binary fission. Organisms within Ny2 appeared to be surrounded by 2 double-layered membranes. Electron-dense forms, commonly observed in adult ticks, were not seen in colonies (Ny1, Ny2, or TsN) from nymphal ticks.
Assuntos
Anaplasma marginale/fisiologia , Anaplasma marginale/ultraestrutura , Dermacentor/microbiologia , Animais , Microscopia Eletrônica , Ninfa/microbiologiaRESUMO
Dermacentor andersoni nymphs were placed in stockinettes and allowed to feed on a splenectomized calf with experimentally induced anaplasmosis when the parasitemia was 3%-5%. Nymphs were selected on each of the 6 days of feeding and every 5 days from repletion through molting to the adult stage (25 days postrepletion); they were killed and midgut tissues were processed and examined by light and electron microscopies. No stages of A marginale were seen in tissues of feeding ticks. Visualization of individual components of gut contents was difficult owing to presence of the concentrated, electrondense blood meal containing hemoglobin. Inclusion appendages were observed in midgut tissues of nymphs at 5 and 10 days postrepletion, but not at 20 or 25 days. The morphology of the appendages was similar to that described for inclusion appendages commonly associated with anaplasmal inclusions in bovine erythrocytes. Some appendages were free in the lumen of the midgut and occurred either alone or with clusters of small vesicular particles. Occasionally, initial bodies like those generally found in bovine erythrocytes were seen with the appendage, but most of them were swollen and appeared to be degenerating. Frequently, inclusion appendages were observed attached to the luminal surface of the midgut cell membrane by a blunt, electron-dense attachment complex. The attachment of the appendage appeared to be extracellular, with the pointed end extending into the lumen. Often, small particles were observed immediately across the cell membrane from where the appendages were attached; the small particles appeared to be generated from the appendage itself and to have passed through the membrane of the midgut cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Anaplasma/ultraestrutura , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasma/fisiologia , Animais , Bovinos , Dermacentor/ultraestrutura , Eritrócitos/microbiologia , Microscopia Eletrônica , Ninfa/microbiologia , Ninfa/ultraestruturaRESUMO
Laboratory-reared Dermacentor andersoni ticks experimentally infected as nymphs with Anaplasma marginale were allowed to feed as adults from 1 to 9 days on susceptible, splenectomized calves to determine when, during feeding, the hematozoan was transmitted from ticks to cattle. In experiment 1, ticks were allowed to feed on calves for 1, 2, 3, 4, 5, or 6 days and anaplasmosis did not result. The same calves were used for experiment 2, and ticks were allowed to feed for 1, 3, 6, 7, 8, or 9 days and anaplasmosis occurred in all calves on which ticks fed for greater than or equal to 6 days. In 2 trials in experiment 3, ticks were allowed to feed on calves for 1 to 9 days. Anaplasmosis developed only in calves on which ticks fed for 7, 8, or 9 days. The prepatent periods shortened with longer tick feeding, and linear regression analysis of combined prepatent periods of both trials of experiment 3 indicated a significant (P = 0.05) slope with an estimated daily decrease of 7.75 days from day 7 to 9 of feeding. There was no apparent correlation between length of tick feeding and severity of clinical signs in those calves that developed anaplasmosis. Seemingly, A marginale can be transmitted to cattle by adult D andersoni ticks no earlier than the 6th or 7th day of feeding.
Assuntos
Anaplasmose/transmissão , Vetores Aracnídeos , Doenças dos Bovinos/transmissão , Dermacentor/microbiologia , Carrapatos/microbiologia , Animais , Sangue , Bovinos , Dermacentor/fisiologia , Comportamento Alimentar , Feminino , MasculinoRESUMO
Infection with Brucella ovis was established by conjunctival instillation in 8 male white-tailed deer (Odocoileus virginianus). Infection was transient in young bucks, but persisted in bucks that were mature when inoculated. The deer were euthanatized and necropsied at various intervals after inoculation. Brucella ovis was recovered from a mature buck at necropsy on postinoculation day 429. Four deer had gross lesions and histopathologic changes of the epididymides. A mature noninfected buck confined for 7 months with an infected buck acquired infection and developed epididymal lesions.
Assuntos
Brucelose/veterinária , Cervos , Animais , Brucella/isolamento & purificação , Brucella/patogenicidade , Brucelose/imunologia , Brucelose/patologia , Suscetibilidade a Doenças , Epididimo/microbiologia , Epididimo/patologia , Masculino , Sêmen/microbiologia , Especificidade da Espécie , Testículo/patologiaRESUMO
Colonies of Anaplasma marginale in midgut epithelial cells of experimentally infected Dermacentor andersoni were studied in adult ticks 1, 3, and 6 months old. Longevity of the parasite in ticks was assessed by evaluating its infectivity for splenectomized calves; calves were exposed by feeding ticks and by inoculation of tick gut homogenates. Longevity was also evaluated by determining size, type, and density of colonies in male and female ticks. The effect of incubation (2.5 days at 37 C) on colony density was also examined for ticks at each age period. All methods used to assess longevity of A marginale in ticks (tick transmission, calf inoculation, and histologic studies) indicated a decrease of the numbers of organisms in 6-month-old ticks. Furthermore, when tick gut homogenates from 6-month-old nonincubated ticks were not infectious for susceptible calves, incubation of ticks before dissection restored infectivity of homogenates. Colonies of A marginale were detected in gut tissues of 6-month-old ticks that were not infective; therefore, infectivity of ticks could not be confirmed merely by presence of A marginale colonies.
Assuntos
Anaplasma/crescimento & desenvolvimento , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasma/classificação , Anaplasmose/microbiologia , Animais , Bovinos , Sistema Digestório/microbiologia , Epitélio/microbiologia , Feminino , MasculinoRESUMO
Newly replete nymphal Dermacentor andersoni (principals) were percutaneously exposed to Anaplasma marginale by injection of either intact or lysed infected bovine erythrocytes. Control nymphs were fed on calves with anaplasmosis. The subsequently molted adults were examined for infection by light microscopy, and companion ticks were tested for infectivity by allowing them to feed on susceptible calves. When they fed as adults, both control ticks and percutaneously inoculated principals transmitted A marginale to susceptible calves. Prepatent periods in calves varied according to the method by which nymphs were infected. Colonies of A marginale were found in all ticks that acquired infection by feeding, but colonies were not observed in any ticks exposed percutaneously. The possible developmental cycle of A marginale in artificially infected ticks is discussed.
Assuntos
Anaplasma/crescimento & desenvolvimento , Anaplasmose/transmissão , Dermacentor/microbiologia , Carrapatos/microbiologia , Animais , Bovinos , Dermacentor/crescimento & desenvolvimento , Sistema Digestório/microbiologia , Eritrócitos/microbiologia , FemininoRESUMO
Three splenectomized dairy calves were inoculated with a Virginia isolate of Anaplasma marginale Theiler and served as an infective source for laboratory-reared Dermacentor andersoni Stiles nymphs. One month after molting, groups of adult ticks were incubated at 37 C for 0, 1.5, 2.5, and 7 days. Gut homogenates were made from ticks representing each incubation period. Twenty-four susceptible, splenectomized dairy calves were each inoculated IV with a gut homogenate extracted from 50 adult ticks and monitored for patent A marginale infection. The prepatent periods were determined and used as a measure of infectivity. Gut homogenates made from ticks that had been incubated for 2.5 days produced infections with the shortest prepatent periods, an average of 28.5 days among 3 trials.
Assuntos
Anaplasma/patogenicidade , Vetores Aracnídeos/microbiologia , Dermacentor/microbiologia , Temperatura , Carrapatos/microbiologia , Anaplasma/crescimento & desenvolvimento , Anaplasmose/transmissão , Animais , Bovinos , Doenças dos Bovinos/transmissão , Feminino , Esplenectomia/veterinária , VirulênciaRESUMO
Hemolymph was collected from adult Dermacentor andersoni Stiles that had been infected with Anaplasma marginale Theiler as nymphs. Before hemolymph was collected, the adult ticks were either incubated and unfed at 37 C for 2.5 days or fed for 6 days on sheep. Hemolymph collected from groups of 100 ticks was inoculated into susceptible splenectomized calves. Smears of hemolymph from the same groups of ticks were prepared for examination by fluorescent antibody technique. Hemolymph from incubated ticks caused anaplasmosis in 2 of 4 trials, and hemolymph from feeding ticks caused anaplasmosis in 4 of 4 trials. Moderately fluorescing bodies were demonstrated in some hemocytes from incubated ticks, whereas hemocytes from feeding ticks contained numerous clusters of brightly fluorescing bodies. Fluorescing bodies were not observed in hemocytes from control ticks.
Assuntos
Anaplasma/isolamento & purificação , Células Sanguíneas/microbiologia , Dermacentor/microbiologia , Imunofluorescência/veterinária , Hemócitos/microbiologia , Hemolinfa/microbiologia , Carrapatos/microbiologia , Anaplasma/crescimento & desenvolvimento , Animais , Bovinos , Feminino , OvinosRESUMO
On each day of feeding on susceptible calves, salivary glands obtained from groups of adult ticks that transmitted Anaplasma marginale were examined for A marginale colonies by use of light microscopy and transmission electron microscopy. On day 8 of feeding, salivary glands were examined, using fluorescein-labeled antibody and methyl green-pyronine stain. Use of fluorescein-labeled antibody consistently revealed small numbers of fluorescent foci in salivary gland acinar cells obtained from ticks that had fed for 8 days. Colonies of A marginale were seen by transmission electron microscopy only in salivary gland acini of male ticks; these colonies could not be identified, using light microscopy, in companion 1-micron plastic sections stained with Mallory stain. Methyl green-pyronine stain, used commonly to detect theilerial parasites in tick salivary glands, did not differentiate A marginale from cytoplasmic inclusions normally found in salivary gland acinar cells.
Assuntos
Anaplasma/crescimento & desenvolvimento , Vetores Aracnídeos/microbiologia , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasma/ultraestrutura , Anaplasmose/transmissão , Animais , Bovinos , Feminino , Masculino , Microscopia Eletrônica , Glândulas Salivares/microbiologia , Coloração e RotulagemRESUMO
Transstadial and transovarial transmission of Anaplasma marginale by Dermacentor variabilis were attempted with with ticks exposed to the organism once by feeding as larvae or nymphs, and twice by feeding as larvae and nymphs. Typical colonies of A marginale were in gut tissues of adults that were infected as larvae, larvae and nymphs, and as nymphs; repeated exposure of ticks did not appear to result in an increase in the number of colonies in the gut of subsequently molted adults nor did it affect severity of the clinical disease that developed in cattle they fed on. In contrast, colonies of A marginale were not found in the midgut epithelium of unfed nymphs exposed as larvae, even though companion nymphs transmitted the parasite, causing severe clinical anaplasmosis in susceptible calves. The organism was not transmitted transovarially by F1 larvae or nymphs from the groups exposed as parent larvae, nymphs, larvae and nymphs, and as adults. Some of the calves fed on by F1 progeny had a few erythrocytic marginale bodies that looked suspiciously like A marginale, as well as postchallenge exposure prepatent periods that were longer than other calves in the transovarial transmission study. Sera from these calves were tested for antibody to A marginale, using a highly sensitive immunoblot technique. Antibodies were not detected in any of the sera.
Assuntos
Anaplasma/crescimento & desenvolvimento , Anaplasmose/transmissão , Vetores Aracnídeos/microbiologia , Doenças dos Bovinos/transmissão , Dermacentor/microbiologia , Carrapatos/microbiologia , Animais , Vetores Aracnídeos/fisiologia , Bovinos , Dermacentor/crescimento & desenvolvimento , Dermacentor/fisiologia , Feminino , Immunoblotting , Larva/microbiologia , Masculino , OviposiçãoRESUMO
Three isolates of Anaplasma marginale--Virginia (VAM), Illinois (IAM), and Florida (FAM)--were compared for infectivity for Dermacentor andersoni. The isolates were selected, in part, because of a tail-like appendage that has been demonstrated in the VAM and IAM, but not in the FAM. Ticks were exposed to the isolates as nymphs either naturally by feeding on a calf with anaplasmosis or artificially by percutaneous inoculation with infected bovine erythrocytes. They were examined for infectivity after molting to the adult stage by determining their capability to transmit the disease to susceptible calves and by demonstrating colonies in tick gut sections. Only those ticks exposed to the VAM proved to be infected with A marginale; ticks naturally exposed and those artificially infected with this isolate transmitted the disease to susceptible calves. Colonies of A marginale were observed only in gut tissues of ticks naturally infected with VAM. The IAM (appendage present) and FAM (appendage absent) could not be found in ticks exposed by either method, indicating that factors other than the presence of inclusion appendages may be involved in infection of ticks by A marginale.
Assuntos
Anaplasma/patogenicidade , Doenças dos Bovinos/microbiologia , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasmose/transmissão , Animais , Bovinos , Doenças dos Bovinos/transmissãoRESUMO
The development of Anaplasma marginale was studied in Dermacentor andersoni nymphs after they had fed on a calf with ascending Anaplasma infection. Gut tissues were collected on day 4 of tick feeding, from newly replete (fed) nymphs and on postfeeding days (PFD) 5, 10, 15, 20, and were processed for light and electron microscopy to determine density of A marginale colonies. Homogenates of gut tissues were prepared from nymphs collected on the same days and inoculated into susceptible, splenectomized calves to test for infectivity. Anaplasma colonies were detected in gut cells on PFD 5, 10, 15, and 20. Although colony density appeared to be higher on PFD 10 and 15, differences were not significant. Nymphal type-1 colonies were detected in highest numbers on PFD 5 and 10, transitional colonies were seen in highest numbers at PFD 10 and 15, and nymphal type-2 colonies were observed only on PFD 20. Gut homogenates that were collected from ticks at 4 days of feeding, when newly replete, and on PFD 20 caused anaplasmosis when injected into susceptible calves, but homogenates made from ticks collected on PFD 5, 10, and 15 were not infective. The data indicate that of the colony types of A marginale that develop in replete nymphs, nymphal type-1 and transitional colonies may contain organisms that are not infective for cattle.
Assuntos
Anaplasma/crescimento & desenvolvimento , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasma/patogenicidade , Animais , Bovinos , Contagem de Colônia Microbiana , Intestinos/microbiologia , Ninfa/microbiologia , Distribuição Aleatória , Fatores de Tempo , VirulênciaRESUMO
The development of Anaplasma marginale in midgut epithelial cells was studied in feeding, transmitting adult Dermacentor andersoni ticks. Laboratory-reared ticks experimentally infected as nymphs were allowed to feed from 1 to 9 days on susceptible calves. Gut tissues from ticks were collected on each day they fed (total, 9 days) and were processed for light and transmission electron microscopy. Colonies of A marginale were abundant during the first 6 days of feeding, after which numbers decreased. Colonies were adherent to the basement membrane of gut cells early during feeding, with resultant flattening of the colonies. Colonies also were seen in muscle cells on the hemocoel side of the basement membrane. Morphologic features of A marginale within muscle cells varied and were similar to those observed in gut cells. In addition, however, a large reticulated form in the colonies was observed in muscle cells and appeared to give rise to small particles by budding. Development of A marginale in muscle cells appears to represent an intermediate site of development between those in gut and in salivary glands.
Assuntos
Anaplasma/crescimento & desenvolvimento , Membrana Basal/ultraestrutura , Dermacentor/microbiologia , Carrapatos/microbiologia , Anaplasmose/microbiologia , Animais , Feminino , Intestinos/ultraestrutura , Masculino , Microscopia Eletrônica , Ninfa/microbiologiaRESUMO
The development and transmission of Anaplasma marginale was studied in Dermacentor andersoni males. Laboratory-reared male D andersoni were allowed to feed for 7 days on a calf with ascending A marginale parasitemia. The ticks were then held in a humidity chamber for 7 days before being placed on 2 susceptible calves. Anaplasmosis developed in the calves after incubation periods of 24 and 26 days. Gut and salivary glands were collected from ticks on each day of the 23-day experiment and examined with light and electron microscopy. Colonies of A marginale were first observed in midgut epithelial cells on the sixth day of feeding on infected calves, with the highest density of colonies found in gut cells while ticks were between feeding periods. The first colonies contained 1 large dense organism that subsequently gave rise to many reticulated organisms. Initially, these smaller organisms were electron-lucent and then became electron-dense. On the fifth day after ticks were transferred to susceptible calves for feeding, A marginale colonies were found in muscle cells on the hemocoel side of the gut basement membrane. A final site for development of A marginale was the salivary glands. Colonies were first seen in acinar cells on the first day that ticks fed on susceptible calves, with the highest percentage of infected host cells observed on days 7 to 9 of that feeding. Organisms within these colonies were initially electron-lucent, but became electron-dense.