Adherencia terapéutica y control de los factores de riesgo cardiovasculares en usuarios de atención primaria / Therapeutic compliance and cardiovascular risk factors control in primary attention users / A aderência terapêutica e o controle dos fatores de risco cardiovasculares em utentes de atenção primária

Objetivo: Identificar la situación que presentan las personas con factores de riesgo cardiovascular respecto a la adherencia terapéutica, y conocer la relación de esta conducta con el control de dichos factores. Método: Estudio de tipo cuantitativo y transversal. La muestra estuvo constituida por 257 personas con diagnóstico de hipertensión arterial, diabetes mellitus tipo 2 y dislipidemias. Para recolectar los datos se revisó la ficha clínica y se utilizó un cuestionario, y la Escala de Conductas en Salud, para medir adherencia terapéutica. Para procesar los datos se utilizó el programa SPSS v15.0; se usaron medidas de tendencia central y de dispersión; para evaluar la asociación entre variables se recurrió a la t de Student. Resultados: La Escala de Conductas en Salud reflejó la baja adherencia de la muestra, ya que solo 4 (1.5%) personas obtuvieron el puntaje máximo, es decir, que siempre siguen las indicaciones entregadas por el equipo de salud. Se encontró que solo el 22.6% tenía controlada la enfermedad. Se encontraron asociaciones estadísticamente significativas entre el control integral de los factores de riesgo estudiados con la escala global de la Escala de Conductas en Salud, y las subescalas Seguimiento de la dieta y Seguimiento de las actividades prescritas. Conclusiones: El control de los factores de riesgo cardiovascular constituye un complejo conjunto de interacciones, en el cual la adherencia terapéutica puede ser solamente uno de los factores relacionados con él, y por esta razón pueden existir otras variables que influyen en el control de estas enfermedades.

Objective: To identify the situation of persons with cardiovascular risks in relation to their therapeutic compliance, and establish the association of this conduct with the control of those risks. Method: Quantitative and transversal study. The sample included 257 persons diagnosed with arterial hypertension, diabetes mellitus type 2, and dyslipidemia. In order to estimate the therapeutic compliance, data were collected through the clinical history, a questionnaire, and a health behavior scale. Data were processed with SPSS v15.0. Central tendency and dispersion measures were used, and the Student's t test was used to estimate the variables association. Results: The health behaviors scale used showed an overall low-therapeutic-compliance level among the participants. Only 4 individuals (1.5%) obtained the maximum score (absolute compliance with the instructions given by the health team). It was also found that only 22.6% in the sample monitored their condition. Statistically significant associations were found between the control of the studied risk factors measured by the global health behaviors scale and the sub-scales of "following the diet" and "following prescribed activities". Conclusions: The control of cardiovascular risk factors implies a set of complex interactions of which therapeutic compliance is probably just one more. In other words, there could also be other variables which have an impact on the control of these illnesses.

Objetivo: Identificar a situação que apresentam as pessoas com fatores de risco cardiovascular referente à aderência terapêutica, e estabelecer a relação dessa conduta com o controle dos fatores. Método: Estudo de tipo quantitativo e transversal. A amostra foi constituída por 257 pessoas com diagnóstico de hipertensão arterial, diabetes mellitus tipo 2 e dislipidemias. Para a coleta de dados revisou-se a ficha clínica e utilizou-se um questionário, bem como a Escala de Condutas em saúde para medir a aderência terapêutica. Para o processamento de dados utilizou-se o programa SPSS v15.0, usaram-se medidas de tendência central e de dispersão, para avaliar a associação entre as variáveis, precisou-se da t de Student. Resultados: A Escala de Condutas em saúde e as subescalas "Continuação da dieta" e "continuação das atividades prescritas". Conclusões: O controlo dos fatores de risco cardiovascular constitui um complexo conjunto de interações no qual, a aderência terapêutica pode ser apenas um dos fatores relacionados com ele, e por esta razão podem existir outras variáveis que influenciam no controlo destas doenças.

Long-term follow-up of radiation accident patients in Peru: review of two cases.

Overexposure to radioactive sources used in radiotherapy or industrial radiography may result in severe health consequences. This report assesses the initial clinical status and the medical and psychological long-term follow-up of two radiation accident patients from Peru during the mid-to-late 1990s: one patient exposed to a radiotherapy (60)Co source in Arequipa, the other patient to a (192)Ir source in Yanango. Commonalities and differences are described. The main causes in both accidents were human error and the failure to apply appropriate safety guidelines and standard operating procedures. Education and training of the personnel working with radiation sources are essential to prevent accidents. The experience gained from the medical management of the two patients is valuable for future treatment of such patients.

Sindrome de prune - Belly: comunicación de un caso clínico / Prune Belly symdrome: a clinic case communication

Se expone el caso de un bebé con Síndrome de Prune Belly, nacido en la maternidad del Hospital Daniel Bracamonte, con una sobrevida de 3 meses, tiempo durante el cual se pudo seguir su evolución. es una malformación congénita rara, más aún en una ciudad con una población no mayor de 150.000 habitantes. Se aprovecha el caso para realizar una revisión de la patología y la descripción correspondiente

Performance of female Rhipicephalus sanguineus (Acari: Ixodidae) fed on dogs exposed to multiple infestations or immunization with tick salivary gland or midgut tissues.

This investigation compared the effects of repeated infestations to immunization of dogs with tick salivary gland or midgut extracts on the feeding and fecundity performances of female Rhipicephalus sanguineus (Latrielle). In each immunized group, three tick-naive dogs were immunized three times with tick salivary gland or midgut extracts, and twice challenged at 21-d intervals by allowing 80 female and 40 male adult ticks to feed on each host. The repeated infestation group of three naive dogs was infested five times at 21-d intervals by the same numbers of ticks. The repeated infestation group showed a trend of reduced tick performance after the third infestation, but some of the tick performance parameters had recovered by the fifth infestation. Tick attachment was reduced by immunization with either tick salivary gland or midgut extract. Immunization with tick salivary gland extract had the greatest impact on the feeding period and engorgement weight of the female ticks. Immunization with tick midgut extract resulted in the greatest reduction of tick fecundity parameters, which included preoviposition, oviposition, and egg-incubation periods in addition to reduced egg production and egg viability. These results confirm that dogs can become resistant to R. sanguineus, and demonstrate that immunization with tick salivary gland or midgut extract has different effects on tick feeding and fecundity.

Humoral immune response of dogs immunized with salivary gland, midgut, or repeated infestations with Rhipicephalus sanguineus.

The antibody (Ab) responses of dogs immunized with adult tick salivary gland (TSG), midgut (TMG), or repeated infestations of Rhipicephalus sanguineus were monitored to determine if there is an association between Ab production and R. sanguineus performance. Tick-naïve dogs were immunized with TSG or TMG and subjected to two challenge infestations. The control group was infested five times at 21-day intervals. The ELISA technique was used to measure Ab levels in sera from these dogs, which expressed different forms of resistance against R. sanguineus. In dogs immunized with TSG or TMG, similar Ab levels were detected against TMG, TSG, muscle, synganglion, and reproductive organs. However, these sera had different Ab levels against egg mass, unfed larvae, fed larvae, and nymph antigens. Ab levels to muscle, nerve, and reproductive antigens were lower than those observed when TMG or TSG antigens were used. Sera from dogs immunized with TMG or TSG responded to most tick stages or tissue antigens, whereas repeated infestation sera showed the lowest response among the three groups.

Evidence and mechanisms of immunosuppression in tick infestations.

The abundance and ubiquity of ticks from ancient times long ago suggested that they have eluded host immunity. In the last 15 years, several authors have demonstrated suppression of the Th1 responses (cell-mediated immunity), and sometimes the Th2 responses (humoral immunity), subsequent to tick infestations in laboratory and natural models. Although the mechanisms to produce suppression are not well-defined yet, evidences for antigenic competition, lymphocyte cytotoxicity, presence of immuno-inhibiting substances in the saliva, and existence of modulators of cytokines in salivary extracts have been reported. Management of tick-induced immunosuppression is essential to replace tick control by acaricide application with more environmentally sound vaccination.

Ifosfamide plus cisplatin as primary chemotherapy of advanced ovarian cancer.

We have performed a phase II study to evaluate the activity and toxicity of ifosfamide and cisplatin as first-line treatment for advanced ovarian cancer. Patients were treated with cisplatin 100 mg/m2 on day 1 and ifosfamide 5 g/m2 in 18-hr continuous infusion on day 1 or 1.5 g/m2 bolus on days 1-5. Between August 1988 and March 1990, 30 women were entered in the trial, 26 of them with measurable disease. The overall clinical response rate was 69% (95% CI: 48-85%), including 34.6% complete responses (95% CI:17-55%). Reassessment laparotomy was performed in 12 cases, and 4 (33%) exhibited a pathologic complete response. For all patients, the median duration of progression-free survival was 14 months, and the median overall survival was 25 months. There were no major differences in the response rate or survival between the two ifosfamide administration modalities. Relevant toxicities were grade IV hematologic toxicity in 11/30 patients and grade IV renal toxicity in 2/30 patients. A patient with grade IV encephalopathy developed a trauma-related cerebral hemorrhage and died 2 months later. The combination of ifosfamide and cisplatin is active in first-line therapy in advanced ovarian cancer, although it does not seem to improve the efficacy or toxicity profile of conventional combinations.

Hyalomma ticks: bovine resistance under field conditions as related to host age and breed.

Field collection of ticks from two breeds of cattle [Native breed (local) and purebred [Friesian)], showed that the number of ticks was higher on purebred than on native cattle. The susceptibility seemed to increase with the age of the animals. Furthermore, breed appeared to exert more influence than age. There was no correlation between the number of ticks associated with each animal, the antibody production and antigens recognized. The immune response under field condition looked more like immune suppression than immune protection.

Comparative immunizing power of infections, salivary extracts, and intestinal extracts of Hyalomma marginatum marginatum in cattle.

Tick concealed antigens have been successful in producing immunity that inhibits tick fertility, but require periodic revaccination and are little effective in preventing tick feeding, which is critical to stop pathogen transmission. Tick natural salivary antigens also induce important immunity, but revaccination may be unnecessary in enzootic areas. In addition these antigens may inhibit tick feeding. We immunized groups of three tick-naive calves with four prior infestations with Hyalomma marginatum marginatum, a salivary extract (SE), or an intestinal extract (IE) of the ticks. The calves were challenged with 100 pairs of homologous ticks and characteristics representing tick feeding or fertility were recorded and compared between groups. The percentage of attachment was inhibited by 46% by the infestation-generated immunity, 47% by the SE-generated immunity, and 0% by the IE-generated immunity. The percentage of engorgement was reduced 40% by the infestations, 57% by the SE, and 29% by the IE. The length of feeding was prolonged 92% by the infestations, shortened 44% by the SE, and not affected by the IE. The weight of the engorged females was decreased 67% by the infestations, 64% by the SE, and 31% by the IE. The percentage of engorged ticks that oviposited was inhibited 52% by the infestations, 27% by the SE, and 63% by the IE. The preoviposition period was prolonged 160% by the infestations, 80% by the SE, and 140% by the IE. The egg weight was reduced 60% by the infestations, 60% by the SE, and 66% by the IE. Taking into account mortality before oviposition, fertility was inhibited 88.2% by the infestations, 87.5% by SE, and 91.4% by the IE. The effect of IE immunization on tick feeding was not significant statistically.

One-session management of cervical intraepithelial neoplasia: a solution for developing countries.

Six hundred thirty-nine patients with CIN on referral Pap were evaluated cytocolposcopically at the first visit and decided whether to be treated the same day or not. One hundred ninety-two patients (30%) were considered negative. Follow-up evidenced later appearance of CIN in five of them. One hundred fifty-three (24%) were candidates for delayed treatment due to conditions contraindicating same-day treatment. Two hundred ninety-four patients (46%) were randomly allocated in LEEP (149) or excisional laser (145) arms, and treated the same day under local anesthesia. Both arms were comparable. There were three microinvasive carcinomas diagnosed in the surgical specimen. LEEP was faster and produced less bleeding than laser, although required a mean of four slices to remove the lesion. Arterial hypertension after anesthetic infiltration was detected in 26% of cases. Two intraoperative and two delayed bleeders required surgery. The size of lesion and surgical defect were larger than those reported in the literature. Margins were involved in 8 patients (2.7%). Only 4.7% (7/149) of patients randomized to LEEP and 3.4% (5/145) with excisional laser had persistent or recurrent CIN on follow-up. Factors predisposing to failure included depth of surgical defect, grade of lesion, and operator's expertise. With this approach, 69% of patients referred for cytology of CIN were adequately managed in the first visit, which contrasts to classical management that reaches the state of treatment in 30% of patients. LEEP appears to be faster, less costly, and requires less expertise. Its use in conjunction with adequate screening is recommended for developing countries.

One-Session Management of Cervical Intraepithelial Neoplasia: A Solution for Developing Countries. A Prospective, Randomized Trial of LEEP versus Laser Excisional Conization

Six hundred thirty-nine patients with CIN on referral Pap were evaluated cytocolposcopically at the first visit and decided whether to be treated the same day or not. One hundred ninety-two patients (30%) were considered negative. Follow-up evidenced later appearance of CIN in five of them. One hundred fifty-three (24%) were candidates for delayed treatment due to conditions contraindicating same-day treatment. Two hundred ninety-four patients (46%) were randomly allocated in LEEP (149) or excisional laser (145) arms, and treated the same day under local anesthesia. Both arms were comparable. There were three microinvasive carcinomas diagnosed in the surgical specimen. LEEP was faster and produced less bleeding than laser, although required a mean of four slices to remove the lesion. Arterial hypertension after anesthetic infiltration was detected in 26% of cases. Two intraoperative and two delayed bleeders required surgery. The size of lesion and surgical defect were larger than those reported in the literature. Margins were involved in 8 patients (2.7%). Only 4.7% (7/149) of patients randomized to LEEP and 3.4% (5/145) with excisional laser had persistent or recurrent CIN on follow-up. Factors predisposing to failure included depth of surgical defect, grade of lesion, and operator's expertise. With this approach, 69% of patients referred for cytology of CIN were adequately managed in the first visit, which contrasts to classical management that reaches the state of treatment in 30% of patients. LEEP appears to be faster, less costly, and requires less expertise. Its use in conjunction with adequate screening is recommended for developing countries.

Relationships and influences between Boophilus microplus characteristics in tick-naive or repeatedly infested cattle.

Six tick-naive male Hereford calves were infested once a month for 6 months with 18,000 Boophilus microplus larvae on the back and with 400 larvae in a cloth bag glued on the lumbar region. Working with the bag ticks, 12 tick characteristics were recorded for each infestation. Each tick attribute was analyzed for significant differences with those of the first infestation (analysis of variance), and for similarity (clustering), degree of relationship (correlation), and concomitant variation (regression) against all the other attributes during the first, third, and sixth infestations. Some attributes were affected maximally by host immunity about the third infestation but recovered later (length of feeding, detachment weight, egg weight, start of oviposition, fertility efficiency index), whereas others continued to be affected until the last infestation (length of oviposition, corpse weight, start of hatching, feeding efficiency index). All analyses showed that weight at detachment and egg weight were closely related, and corpse weight was partially related to these two. All other natural characteristics were largely independent. Length of feeding showed no significant relation with weight at detachment nor length of oviposition with egg weight. These findings suggest that different tick functions are independently affected by host immunity and recommends against estimating general anti-tick resistance by the evaluation of only a few tick characteristics.

A review on vaccination against protozoa and arthropods of veterinary importance.

The recent advances in immunology and biotechnology have stimulated much research on the control of parasitic diseases through vaccination. This is a review of the state of the art regarding important protozoan and arthropod veterinary parasites. A live oocyst vaccine for avian coccidiosis is still in use but much work has been done on the identification, cloning, and assay of protective antigens. The sporozoites of Eimeria tenella have been the preferred subject and at least four recombinant antigens have already been tested with partial success. Premunization against babesiosis is still widely used in Latin America as is a live vaccine with attenuated parasites in Australia. At least three Babesia bovis and three Babesia bigemina antigens that generate partial protection have been produced as recombinant proteins. A vaccine against canine babesiosis is being commercialized in France. Infection-treatment is still used to vaccinate against Theileria parva and a schizont vaccine against Theileria annulata. Recombinant sporozoite antigens have been assayed with partial success against both species but the identification and administration of protective schizont antigens, regarded as the most important, still requires considerable work. The immunological control of African trypanosomoses is still impaired by the antigenic variation that the parasites experience during the infection. Although some possibilities exist, most specialists are pessimistic about the promise of developing a vaccine in the near future. Control of Boophilus ticks with an occult tick intestine recombinant antigen seems to have potential in inhibiting reproduction of the tick but salivary antigens appear to be more effective at inhibiting feeding and pathogen transmission. Vaccination with a Hypoderma protein, recently cloned, has induced 90% protection against subsequent infestations. It is very likely that effective vaccines against veterinary parasites will become available in the near future.

Inhibition and recovery of tick functions in cattle repeatedly infested with Boophilus microplus.

Six tick-naive male Hereford calves were infested with about 18,000 Boophilus microplus larvae, 400 in a cloth bag, once a month for 6 mo. Working with the bag ticks, 12 tick characteristics were recorded for each infestation. Manifestations of resistance to some attributes appeared by the second infestation, peaked by the third (detachment weight, egg weight, fertility index) or fourth (feeding length, start of oviposition), and vanished by the fifth or sixth. Resistance to corpse weight, oviposition length, start of eclosion, feeding index, and survival developed more slowly but continued until the last infestation. Lymphocyte transformation after the fifth infestation was normal for concanavalin A and augmented in only 2 calves for phytohemagglutinin. In each infestation and at the end of all infestations some calves were significantly more resistant to some tick characteristics. There was no relationship between natural resistance and the ability to mount an acquired resistance. We concluded that B. microplus can depress or evade host's immunity, that resistance to different tick functions occurs independently, that natural and acquired resistance are unrelated, and that there exist genetic differences in natural or acquired resistance to the tick among seemingly homogeneous animals.

Immunity to Toxocara vitulorum repeated infections in a rabbit model.

Eleven rabbits were infected with 10 embryonated eggs of Toxocara vitulorum per g body weight on Days 0, 35 and 72. Embryonated eggs and larvae were enumerated in feces on Days 1-3 after each infection. Two rabbits were killed and larvae were enumerated in small intestine, liver, lungs, skeletal muscles, heart, kidney, brain, eye, uterus, and mammary glands on Days 5, 15, 30, 65 and 101. Serum was obtained on Days 0, 5, 15, 30, 42, 50, 65, 78, 86 and 101 to perform enzyme-linked immunosorbent assays (ELISAs) and Western blots against an extract of embryonated eggs. Between 4 and 10% of the administered parasites, almost all embryonated eggs, were found in the feces after the first or second infection, but 32% (27% of them larvae) after the third. Yields of tissue parasites were 4.1% of the administered dose on Day 5, 2% on Day 15, and 0.8% on Day 30 of the first infection, 0.1% on Day 30 of the second infection, and 0.06% on Day 30 of the third. Larvae were found only in liver, lungs and muscle, including heart. Larva content declined steadily in liver and lungs from Day 5 to 30 of the first infection, was absent in the liver at Day 30 of the second, and in both organs at Day 30 of the third. Muscle larva content increased from Day 15 to 30 of the first infection, and persisted throughout the third infection. Production of IgM antibody was minimal, IgG and the sum of IgMGA antibodies increased slightly or moderately after the first and second infections, but dramatically after the third. Western blots revealed the first antigens (12) by Day 15 of the first infection. Their total number increased with time and number of infections, but some antigens disappeared, whereas new antigens appeared in the course of the observations. Four antigens (32,500-41,000 mol.wt.) may be related to protection. Comparison of the Western blot patterns of two rabbits showed differences in the antigens, recognizable for each rabbit.

Evidence of immunosuppression by Demodex canis.

Three clinically normal beagles, 3 beagles with localized demodectic mange (LDM), and 3 beagles with generalized demodectic mange (GDM) were investigated simultaneously 1-3 and 4-6 weeks from the appearance of the clinical signs. Blood clinical examination and reactivity of peripheral lymphocytes to Con A and PHA were investigated in the first instance, and reactivity to Con A, PHA, and LPS in the second. Eight aliquots were used in each blastogenesis assay for each dog. All dogs were negative for rheumatoid factor. The results of blastogenesis showed that many observations were distributed non-normally, and that not all dogs in each group responded homogeneously. Comparison of blastogenesis results between dogs demands careful statistical analysis. Responses to mitogens were normal in all dogs at 1-3 weeks except for the LDM dogs that showed an increased response to PHA. Only the response to Con A was moderately inhibited in the LDM dogs at 4-6 weeks. All responses were severely depressed in the GDM dogs at 4-6 weeks. This means that immunosuppression follows rather than precedes the clinical manifestations of GDM, and implies that the phenomenon is induced by the parasite or the host's reaction to it.

Effect of host sex and litter on the population dynamics of Echinococcus granulosus in dogs.

Twenty-one Beagle dogs consisting of 10 males and 11 females and belonging to 3 litters were infected with 60,000 E. granulosus protoscolices each. They were killed on day 40, the parasites from their intestines recovered, and the number of worms, average number of proglottides per worm, average length per worm, percentage of worms with a uterine cavity, and percentage of egg-bearing worms were determined for each dog and analyzed per sex and litter. On average, the dogs had 1,253 +/- 339 worms (means +/- standard error) with 2.42 +/- 0.1 proglottides, were 1.59 +/- 0.07 mm long, and 25.6 +/- 4.8% of the worms presented a uterine cavity and 1.2 +/- 0.6% bore eggs. The number of worms exhibited a bimodal distribution with 19 dogs having less than or equal to 2,565 worms and 2 greater than or equal to 5,520 worms. Average number of proglottides also showed a bimodal distribution with 7 dogs having less than or equal to 2.1 proglottides per worm and 14 dogs having greater than or equal to 2.4 proglottides per worm. The parasites were significantly more numerous in females than in the males (1,964 +/- 573 vs. 681 +/- 202), had more proglottides (2.67 +/- 0.08 vs. 2.15 +/- 0.16), and were longer (1.72 +/- 0.07 vs. 1.44 +/- 0.11 mm). The percentages of parasites with a uterine cavity (27.8 +/- 5.9 vs. 23.2 +/- 8.1) or bearing eggs (1.0 +/- 0.5 vs. 1.5 +/- 1.8) were comparable in females and males.(ABSTRACT TRUNCATED AT 250 WORDS)

Biology and pathophysiology of Toxocara vitulorum infections in a rabbit model.

Ten female New Zealand rabbits were infected via stomach intubation with eggs of Toxocara vitulorum at a dosage of 10 embryonated eggs per gram of body weight on Days 0, 35 and 72. Ten or 4% of the administered parasites passed in the feces during the 3 days following the first or second infection, but 32% after the third infection. Many larvae were passed in the third infection, but not in the first or second. Tissue parasite yields were 4.1% on Day 5, 2% on Day 15, 0.8% on Day 30, 0.1% on Day 65 and 0.06% on Day 101. Five hundred and ninety-three larvae were recovered from liver, 243 from lungs and 0 from muscles on Day 5; 282 from liver, 138 from lungs and 21 from muscles on Day 15; 151 from liver, 21 from lungs and 50 from muscles on Day 30; 0 from liver, 26 from lungs and 15 from muscles on Day 65; 0 from liver, 0 from lungs and 9 from muscles on Day 101. No larvae were found in other tissues. The size of the muscle larvae at 30, 65 and 101 days indicated that the parasites did not develop beyond the infective stage and suggested that they were probably hypobiotic organisms. Erythrocytes, packed cell volume and monocytes decreased, but eosinophils and basophils increased, after each infection. Serum enzyme levels indicated that liver damage occurred only after the first infection, but muscle injury occurred after each infection and was increasingly more precocious after each infection.

Antigens of Amblyomma americanum ticks recognized by repeatedly infested sheep.

Sera were taken from 3 sheep that had been infested 5 times with Amblyomma americanum and that exhibited manifestations of humoral depression to homologous antigens and anti-tick resistance. Proteins extracted from the intestine or salivary glands of unfed ticks or salivary glands from partially (3-day) fed ticks were analyzed by polyacrylamide gel electrophoresis (PAGE) and sodium dodecyl sulfate-PAGE. Antigens recognized by the sheep in the same materials before and after each infestation were analyzed by western blots. The sheep responded to 44 antigens. Nine to 23 antigens were recognized by the preinfestation sera and the sera of 2 gnotobiotic sheep. Four antigens (34,000, 36,500, 38,000, and 115,000 MW) were revealed conspicuously by the serum of the first infestation but very weakly or not at all by the sera of the third infestation onward. Two antigens (35,500 and 29,000 MW) from fed salivary glands were revealed only by sera taken after manifestations of resistance had appeared. These antigens may be responsible for anti-tick protection. The 29,900 MW antigen was present also in salivary extracts of Boophilus microplus.

Manifestations of immunity in sheep repeatedly infested with Amblyomma americanum ticks.

Three sheep were infested 4 times with 100 Amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. Characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and ELISA antibodies to tick salivary gland extracts were studied at each infestation. On average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, and 35% survived to detachment during the first infestation. During the fourth infestation, they detached at 17.3 +/- 0.8 days, weighed 321 +/- 14.4 mg, engorged 18.8 mg per day on average, and 23% survived to detachment. On average, oviposition of female ticks fed on tick-naive sheep started at 11.8 +/- 0.6 days of detachment, the egg mass weighed 236 +/- 13.2 mg, 43% of the female weight turned into eggs, and 89% of the ticks that detached survived to oviposition during the first infestation. During the fourth infestation, oviposition started at 15.1 +/- 0.5 days, the eggs weighed 103 +/- 9.9 mg, 13% of the tick weight became eggs, and 67% of the ticks survived to oviposition. On average, eclosion started at 35.4 +/- 0.9 days of oviposition and 83% of the egg batches hatched in the first infestation. During the fourth infestation, eclosion started on day 34.9 +/- 0.7, and 47% of the egg batches hatched. Anti-tick resistance was expressed as an inhibition of feeding, fertility, and offspring development.(ABSTRACT TRUNCATED AT 250 WORDS)