The ixodid tick species attaching to domestic dogs and cats in Great Britain and Ireland.

The species of ixodid ticks, attached to dogs and cats presented to veterinary practices in Great Britain and Ireland were identified. Most host animals carried only one tick species with Ixodes ricinus Linné (Acari: Ixodidae) being the most common, identified on 52% of animals, Ixodes hexagonus Leach (Acari: Ixodidae) the second most common (on 39%) and Ixodes canisuga Johnston (Acari: Ixodidae) the third most common (on 11%). A significantly higher proportion of dogs than cats carried I. ricinus, while I. hexagonus was more frequently carried by cats. One animal carried a single specimen of Haemaphysalis punctata Canestrini & Fanzago (Acari: Ixodidae), one carried a Dermacentor reticulatus Fabricius (Acari: Ixodidae) but none carried Rhipicephalus sanguineus Latreille (Acari: Ixodidae). This indicates that the latter two species, vectors of 'exotic' tick-borne diseases, remain at low densities in Great Britain and Ireland. Retrospective information on exposure of the animals to different habitats and geographic regions was collected by questionnaire and subject to contingency table and logistic regression analysis. Woodlands and moorlands were habitats significantly associated with I. ricinus attachment. Exposure to urban parks was significantly associated with I. hexagonus attachment and exposure to boarding kennels and catteries was significantly associated with I. canisuga attachment. Ixodes hexagonus, rather than I. ricinus, was the ixodid tick species most likely to be encountered by urban populations of dogs and cats and, by inference, possibly also humans. The implications of these findings, for the transmission of tick-borne pathogens to dogs, cats and humans are discussed.

Efficacy of an ivermectin controlled-release capsule against nematode and arthropod endoparasites in sheep.

Five controlled trials were conducted in Germany or in the United Kingdom, using 74 female sheep of merino or Dorset horn breeds, to evaluate the efficacy of an ivermectin controlled-release capsule against naturally acquired or induced infections of gastrointestinal nematodes, lungworms and nasal bot larvae and against incoming infections with gastrointestinal and pulmonary nematodes. Half of the animals were treated with one ivermectin controlled-release capsule that delivered ivermectin at the rate of 1.6 mg per day for 100 days while the other half remained untreated. Parasites were counted 21, 28, 35 or 56 days after administration of the capsule. The treatment was highly effective (> or = 99 per cent) against established parasites of the following species: Haemonchus contortus (adults and fourth-stage larvae), Ostertagia circumcincta, O pinnata, O trifurcata, Ostertagia species fourth-stage larvae, Trichostrongylus axei, T colubriformis, T vitrinus, Cooperia curticei, Nematodirus battus, N filicollis, Strongyloides papillosus, Chabertia ovina, Oesophagostomum venulosum, Trichuris ovis, Tr skrjabini, Dictyocaulus filaria, Protostrongylus rufescens and Oestrus ovis (larvae). The treatment prevented the establishment of the gastrointestinal nematodes H contortus, O circumcincta, T axei, T colubriformis, C curticei, N battus, N filicollis, Ch ovina, Oe vennulosum and the establishment of the lungworm D filaria by > 99 per cent compared with untreated controls (P < or = 0.01).

High frequency oscillation in newborn infants with respiratory failure.

OBJECTIVE: To report ventilation strategies, survival and complications in 39 outborn infants treated with high frequency oscillatory ventilation (HFOV). METHODOLOGY: Data were collected prospectively between 1 May 1992 and 31 December 1993 on all infants treated with HFOV who had severe respiratory failure despite optimal conventional ventilation. RESULTS: Twenty-eight out of 39 (72%) survived. Of the 15 infants with birthweights < 1500 g, eight survived. Best survival rates were for infants with pulmonary interstitial emphysema with air leak (4/5) and for infants of birthweight > 1500 g with hyaline membrane disease (8/8), and meconium aspiration syndrome (7/7). Three infants deteriorated while on HFOV and required extracorporeal membrane oxygenation. Complications were: (i) development of pulmonary interstitial emphysema (1); (ii) recurrence of pneumothorax (3); (iii) hypotension (2); and (iv) bronchopulmonary dysplasia (9). One of the eight infants weighing < 1500 g who received HFOV in the first week of life developed periventricular haemorrhage. CONCLUSION: The initial results of HFOV for severe failure were encouraging although a learning curve was encountered with its introduction.

Increased respiratory drive as an inhibitor of oral feeding of preterm infants.

This study was designed to determine whether increased respiratory drive induced by inhalation of carbon dioxide would alter the reflex and voluntary components of feeding. For 10 preterm infants (mean +/- SD: postconceptional age at study, 34 +/- 2 weeks; weight, 2.1 +/- 0.2 kg), four trials of nutritive feeding were offered: two while the infants were inhaling a gas mixture containing 40% oxygen and two while the infants were breathing 40% oxygen and 7% carbon dioxide. Nasal airflow was monitored with a pneumotachygraph. Pressure-sensitive catheters in the esophagus and in the feeding nipple were used to detect swallowing and sucking. Sucking frequency and pattern, rate of swallowing, end-tidal carbon dioxide, and minute ventilation were recorded for 30-second epochs during feeding. When the inhaled gas mixture was switched from 40% oxygen to 40% oxygen and 7% carbon dioxide, sucking frequency decreased from 53 +/- 10 to 48 +/- 12 and from 54 +/- 12 to 40 +/- 19 sucks/min, respectively (p < 0.005). Frequency of swallowing also fell during the two feeding epochs on 7% carbon dioxide, from 45 +/- 15 to 40 +/- 15 and from 43 +/- 14 to 31 +/- 16 swallows/min (p < 0.003). Thus acute hypercapnea was accompanied by a decrease in rate of both sucking and swallowing during nutritive feeding. Increased ventilatory drive may directly inhibit nutritive feeding behavior in premature infants.

Alae nasi activation in preterm infants during oral feeding.

Preterm infants may demonstrate impaired ventilation during oral feeding with resultant hypoxemia and hypercarbia. This study was designed to determine whether infants activate a representative upper airway muscle, the ala nasi, in response to these ventilatory changes. Ten preterm infants (postconceptional age at study 35 +/- 4 wk, weight 2.2 +/- 0.1 kg) were studied during a control period, continuous feeding, subsequent intermittent feeding, and a period of nonnutritive sucking. Nasal airflow was measured with a pneumotachometer to quantify minute ventilation. The alae nasi electromyogram (EMGAN) was recorded with surface electrodes, and sucking pressure was detected by a catheter in the feeding nipple. End-tidal CO2 and O2 saturation were also recorded during each period. The percentage of breaths associated with EMGAN activity increased from 41 +/- 13% during the control period to 95 +/- 5% and 93 +/- 7% during continuous and intermittent sucking, respectively (p < 0.05). Eighty-seven +/- 5% of EMGAN activity occurred during inspiration. During continuous and intermittent sucking, the amplitude of EMGAN activity also increased (6.8 +/- 5.2 and 6.7 +/- 4.0 arbitrary units/breath, respectively) compared with the control period (2.4 +/- 2.8 units/breath, p < 0.05). In association with the increase in EMGAN activity, O2 saturation fell from 98 +/- 1% in the control period to 95 +/- 1% during both continuous and intermittent feeding (p < 0.05), and minute ventilation fell from 274 +/- 80 mL/min/kg during the control period to 190 +/- 81 and 208 +/- 57 mL/min/kg during continuous and intermittent feeding, respectively (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)