The incrimination of Aedes (stegomyia) aegypti as the vector of Dirofilaria repens in Nigeria

Six local species of culicides were identified as the common mosquitoes in Zaria, out of 15 species captured using various adult and larval collection methods. These common culicides are Culex pipiens fatigans, Anopheles gambiae grp., Mansonia africana, Culex pipiens pipiens, Aedes (stegomyia) aegypti and Aedes vittatus. They were each fed directly on a local dog naturally infected with Dirofilaria repens to evaluate their refractoriness/susceptibility to dirofilarial infection. In a number of donor-feeding trials, 39. 4% Culex pipiens fatigans; 58.9% An gambiae grp.; 60.5% Mansonia africana; 1.8% of Culex pipiens pipiens; 23.4% Ae aegypti and 3.3% of Ae vittatus successfully fed on the microfilaraemic host. Only Aedes aegypti was susceptible to the infection as all 40 (100%) Ae aegypti reaching 10-14 day post-blood meal had infective (L(3)) larvae of D. repens. The remaining five species were refractory. The microfilariae in the five non-susceptible mosquitoes were always found trapped in the blood meal in the insects midgut (stomach). These trapped microfilaria were dead by the 2nd day in the insect's midgut. However, in the susceptible Ae aegypti, the microfilariae were set free from the blood meal in the midgut and within 24h migrated to the malpighian tubules (MT) of the mosquitoes. All Ae aegypti dissected 5-7 day post-infective blood meal showed the typical quiescent sausage stage (L(2)) larvae in the malpighian tubules. At day-10 post-blood meal, relatively active infective (L(3)) larvae of D. repens were found in the MT; and by day 12-14, highly motile infective larvae had reached the insect's head and proboscis, with infective larvae occasionally oozing out during dissection through the tip of the proboscis. The rate of development of D. repens to infective larvae was faster in mosquitoes infected in July when the environmental temperature was 24.5 degrees C than those infected in November when the temperature was 22.5 degrees C. The latter were delayed for 4 days. The breeding sources of Ae aegypti, the local vector implicated were also identified. As no particular vector of this zoonotic filaria has been identified previously in Nigeria, these findings could make any control programme more focussed and easier.     

Exfoliative colpocytology: a method for the diagnosis of Capuchin monkey filariasis?

During vaginal fluid examinations (Papanicolaou) to study the physiological sexual cycle of Cebus sp., abundant Dipetalonema gracile microfilariae (110-160 microns x 4-5 microns, without a sheath) were encountered in the genital fluid, but not in peripheral blood. Considering the great difficulty in diagnosing this obscure parasitosis, exfoliative colpocytology was found to be an efficient diagnostic.     

Aedes vexans and Culex pipiens as the potential vectors of Dirofilaria immitis in Central Turkey

This study was carried out to investigate the potential vectors and relative mosquito infection rates of Dirofilaria immitis throughout two mosquito seasons (2008-2009) in Kayseri province where is located in Central Anatolian part of Turkey. For this aim, totally 1198 genomic DNA pools, extracted and grouped according to the species and collection site (1-17 specimens/pool) from 6153 mosquito specimens, were examined by PCR using species-specific primers for D. immitis. The captured mosquitoes from 46 focuses were survived under in vitro conditions for 7 days to allow the development of larval stages of D. immitis. DNA extraction was performed individually to both thorax-head and abdomens in order to determine infective and infected mosquito specimens, respectively. The most abundant mosquito species in the study area was determined as Ae. vexans (51.7%) and this was followed by Cx. pipiens (42.1%), Cx. theileri (3.1%), Cs. annulata (1.5%), An. maculipennis (1.0%) and Cx. hortensis (0.6%). The PCR results indicated that 9/312 and 12/312 pools from Ae. vexans abdomens and thorax-heads were positive for filarial DNAs, respectively where as 3/241 pools of each abdomens and thorax-heads from Cx. pipiens were positive for D. immitis DNAs. The minimum infection rates (MIRs) for Ae. vexans and Cx. pipiens were calculated as 0.41 and 0.12, respectively. Although D. immitis DNA's were found in both pools from Ae. vexans and Cx. pipiens, the calculated MIRs provide evidence that Ae. vexans could be the main potential vector of D. immitis in Kayseri.     

Larvicidal activity of two Algerian Verbenaceae essential oils against Culex pipiens

The purpose of this study was to evaluate the bioactivity of essential oils extracted from the leaves of Verbena officinalis and Lantana camara L. for the control of Culex pipiens. Triplicate bioassays were performed with fourth larval instars of C. pipiens (n=25 per replicate) with solutions at 1, 5, 10, 50, 100 and 500 μL/L of V. officinalis and L. camara L. extracts. Cumulative mortalities were determined 3, 6, 12 and 24h after treatment. Results showed cumulative mortalities, at three (3) hours to be 30.0 ± 2.9% and 14.8 ± 1.5% and achieve 43.3 ± 1.9% and 44.4 ± 3.1% after 24h exposure time, at 100mg/L of essential oil from L. camara and V. officinalis, respectively.     

Apparent propagation of the equine infectious anemia virus in a mosquito (Culex pipiens quinquefasciatus Say) ovarian cell line.

A tissue culture of Culex pipiens quinquefasciatus Say ovarian cells appeared to support the growth of equine infectious anemia (EIA) virus. Shetland ponies inoculated with 2nd, 7th, 9th, and 11th passages of mediums harvested from infected tissue culture had clinical signs of the disease and became EIA positive on 11, 19, 23, and 43 days after inoculation, respectively.     

Ingestion of microfilariae from different sources by Culicoides nubeculosus (Diptera: Ceratopogonidae) through an artificial membrane

Laboratory-hatched Culicoides nubeculosus midges were membrane-fed on cattle blood containing various Onchocerca microfilariae which had been isolated from the hides of red deer (Cervus elaphus) and from Australian and native German cattle. All microfilariae were ingested through the membrane except those of O. tarsicola, which were too large. Onchocerca gibsoni and O. lienalis reached the thoracic musculature, but no further development occurred. Microfilariae of O. flexuosa developed to the "sausage" stage. Microfilariae of O. gutturosa developed to the infective larval stage within 9 days at a temperature of 25 degrees C.     

Skeletal muscle fiber size in untrained and endurance-trained horses.

The mean area and minimal diameter of 3 histochemically determined myofiber types (1, 2A, and 2B; myosin ATPase in acid buffer) were calculated in middle gluteal muscle biopsy specimens from 62 stallions, 47 Andalusians and 15 Arabians, ranging in age from 6 to 12 years. Fourteen Andalusians and 7 Arabians were untrained, and the remainder were actively endurance-trained. The 6-month training schedules involved walking, slow trotting, and cantering. Fourteen Andalusians were moderately endurance-trained, whereas the other 19 Andalusians and 8 Arabians were strongly endurance-trained. Significant differences were not recorded between untrained and endurance-trained Arabians with respect to the area (type 1, 3,194 +/- 869 microns 2 and 3,150 +/- 370 microns 2; type 2A, 3,819 +/- 890 microns 2 and 3,380 +/- 356 microns 2; and type 2B, 4,872 +/- 962 microns 2 and 4,417 +/- 646 microns 2) or minimal diameter (type 1, 52.2 +/- 7.4 microns and 52.8 +/- 3.1 microns; type 2A, 58.1 +/- 6.7 microns and 55.0 +/- 2.8 microns; and type 2B, 65.3 +/- 6.4 microns and 63.4 +/- 4.3 microns) of the 3 fiber types, nor between untrained and endurance-trained Andalusians with respect to the area (untrained, 3,990 +/- 690 microns 2; moderately endurance-trained, 3,882 +/- 347 microns 2; and strongly endurance-trained, 3,758 +/- 510 microns 2) and minimal diameter (untrained, 58.1 +/- 4.7 microns; moderately endurance-trained, 59.7 +/- 2.7 microns; and strongly endurance-trained, 58.7 +/- 4.5 microns) of 2A fibers.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skin layer thickness at the ear of the domesticated pig,with special reference to the use of the ear integument for human dermatological research

Based on a shrinkage-free methodical approach (special plastic resin embedding, frozen section technique) and histological routine staining, the thickness of the different skin layers was measured from 15 regions of the outer and the inner side of the porcine auricle. Mean thickness values were for the str. corneum: 19 microns outside/20 microns inside, vital epidermis without ridges: 52 microns outside/56 microns inside, dermis: 1175 microns outside/1112 microns inside, hypodermis: 1024 microns outside/741 microns inside, perichondrium: 295 microns outside/220 microns inside. When both sides of the auricle were compared, it became obvious that the outer side generally had a thicker dermis (1140-1290 microns) and hypodermis (780-1150 microns), whereas the inner side had a thicker vital epidermis (50-60 microns) and deeper epidermal ridges (145-165 microns). The results are discussed with regard to corresponding findings from the human skin, and one region of the outer side of the porcine auricle is recommended as suitable for human dermatological research.     

Spread of equine lungworm (Dictyocaulus arnfieldi) larvae from faeces by Pilobolus fungi

Between 10 and 25% of the Dictyocaulus arnfieldi larvae excreted in faeces from a naturally infected donkey were harvested as infective stages from faecal cultures by means of Pilobolus fungi. The faeces were collected between 24 and 56 hours after drenching the donor animal with Pilobolus spores and kept at 16 +/- 2 degrees C. Most larvae were collected between the 5th and the 8th day of culturing during which period fructification and sporangium discharge also peaked. The sporangia and the adhering larvae were collected in Petri dishes inserted between the faecal mass and a light source. All recovered larvae were viable. A mean larval length of 368 microns (range 312-440 microns) and width of 14.6 microns (range 12-20 microns) was recorded for the infective stage. The method was found suitable for the recovery of infective stages for experimental purposes. The authors suggest that the Pilobolus mechanism play an important part in the spread of equine lungworm infection under field conditions similar to the situation in bovine lungworm (Dictyocaulus viviparus) infection.     

A duplex real-time polymerase chain reaction assay for the detection of and differentiation between Dirofilaria immitis and Dirofilaria repens in dogs and mosquitoes

This study describes a duplex real-time polymerase chain reaction (PCR) assay for the detection and differentiation between Dirofilaria immitis and Dirofilaria repens in dog blood and mosquitoes. Regions of a cytochrome oxidase 1 (cox1) mitochondrial DNA fragment and the second internal transcribed spacer (ITS-2) of nuclear ribosomal DNA were amplified from microfilariae and adult worm samples, using a sensitive SsoFast? EvaGreen(?) based real-time PCR method coupled with melting-curve analysis. The limit of the real-time PCR in detecting microfilaria and adult worm DNA was also tested both in dog blood and in artificially infected microfilarial. Two peaks at different melting temperatures (T(m)) for D. immitis (mean ± SD=75.7 ± 0.3°C) and D. repens (mean ± SD=70 ± 0.7°C), respectively, were obtained for microfilarial and adult positive controls of both species when examined separately and together. The real-time PCR protocol was also efficient in detecting microfilarial and adult DNA of both species when tested in samples spiked with DNA from Aedes albopictus, in Aedes aegypti experimentally infected by D. repens and in Culex pipiens naturally infected by D. repens and D. immitis. The high sensitivity of real-time PCR confirmed its reliability in detecting small amounts of genomic DNA either in dog blood or mosquitoes (2.5 pg/μl and 3 × 10(-1)pg/μl for D. immitis and D. repens, respectively). This assay is proposed as a tool for the epidemiological surveillance of the two most important Dirofilaria species in areas where they are endemic and sympatric.     

Vergleichende Untersuchungen an Haaren von Pudu pudu und europäischen Cerviden

The awn and the fur hair of Pudu were investigated. Values of the length are between 14 and 56 mm for the awn hair, and 9 to 36 mm for the fur hair. Hair thickness--especially at the thickest point--ranges from 140 to 236 microns for the awn hair and from 19 to 106 microns for the fur hair. The values of the cuticle scales are between 12 and 18 microns for the length and between 41 and 66 microns for the width. The shape of the scales is rectangular in the basal three quarters (R) and becomes crenated (R/Z) in the apical quarter. The medulla is continuous with large hollow vesicles. The similarity to the hair of european red deer is surprising.     

Capillaries of the myocardium of Lama (Lama glama)

The heart of 12 adult llamas, one female and 11 males, 2-7 years of age, was studied gross-anatomically (absolute and relative heart weight) and microscopic-anatomically (left and right ventricular wall, left auricle). Comparing the 9 younger animals (2-3 years old) with the 3 older llamas (5-7 years old) a significant increase of the absolute heart weight and of the number of capillaries per mm2 and a significant decrease of the intercapillary distance in the left ventricular wall was found. This results in an increase of capillarity in the studied heart regions (5.5% compared to 6.9%). The simultaneous increase of the capillary-to-myocyte-ratios from 0.9 to 1.1 shows a significant correlation to the cross-sectional area of the myocytes (r = 0.79) and an also significant but negative correlation to the number of myocytes per mm2 (r = -0.82). In both groups the cross-sectional area of the myocytes and their diameter differs significantly in the three regions of the heart (left ventricular wall--214 micron 2 resp. 17.5 microns; right ventricular wall--156 micron 2 resp. 15.5 microns; left auricle--96 micron 2 resp. 11.5 microns). It is to be supposed, that the morphological conditions of the cardiac vascular supply of llamas living in an altitude of 4000 m are improving with age.     

Immunological analysis of agglutination in Dirofilaria immitis microfllariae

The mechanism of agglutination phenomenon of Dirofilaria immitis microfilariae was analyzed. Circulating microfilariae were collected from a D. immitis-infected microfilaremic dog and cultured in the several kinds of sera from dogs and animals. The agglutination of D. immitis microfilariae is a specific phenomenon due to some immune complexes formed with the anti-microfilarial antibody, heat-instable factor(s) and excretory-secretory products of microfilariae. Only live microfilariae were agglutinated and the agglutinated microfilariae remained alive as long as 27 days in culture in vitro.     

A case of canine filariasis due to Dipetalonema reconditum (Grassi 1889) in Nigeria

The clinical findings and the result of periodicity studies in a 41/2- year-old dog with high microfilaraemia due to the microfilariae of Dipetalonema reconditum are presented. The main clinical findings were a dermatosis and emaciation. The microfilaraemia tended to exhibit a nocturnal cyclic variation with the peak occurring between 04.00 hours (4.00 a.m.) and 05.00 hours (5.00 a.m.) and the lowest level between 12.00 hours (12.00 noon) and 14.00 hours (2.00 p.m.).     

Onchocerca gutturosa and Onchocerca lienalis in cattle: variation in length of microfilariae by site of recovery

Dermal microfilariae recovered from specimens obtained from umbilical and cervical sites of cattle infected with adult Onchocerca gutturosa alone or with adults of O gutturosa and O lienalis were measured and compared with uterine microfilariae obtained directly from gravid female worms of each species. Uterine microfilariae of O gutturosa were longer than dermal microfilariae obtained from cattle harboring only adults of O gutturosa. Dermal microfilariae were recovered from umbilical and cervical sites in these cattle. Those found at the cervical site had lengths equal to or greater than lengths of microfilariae recovered from the umbilical site. There was a significant (P less than 0.0001) shift in length across populations of microfilariae of O gutturosa from various sites in its bovine host, with a progressive decrease in length between microfilariae recovered from the worm's uterus, microfilariae from the cervical dermis, and microfilariae from the umbilical dermis, respectively. A similar direct comparison was not possible for microfilariae of O lienalis, because none of the cattle was infected with only adult worms of this species. In an indirect comparison, microfilariae of O lienalis were identified at the umbilicus, but their presence in the cervical region could not be determined unequivocally because of confounding of microfilariae length by concurrent infection with O gutturosa. Uterine microfilariae from O lienalis were longer than uterine microfilariae of O gutturosa, although a degree of overlap in the range of measurements existed between species.     

Efficacy of ivermectin against Onchocerca cervicalis microfilarial dermatitis in horses

Forty horses having microfilariae of Onchocerca cervicalis in association with dermatitis, alopecia, and pruritus on the ventral midline were given a single IM injection of 0.2 mg of ivermectin/kg of body weight (June to August 1981). Microfilarial counts in the 40 horses ranged from 18 to 42,446 microfilariae/skin snip on the day of treatment, and histopathologic examination of these skin sections indicated a chronic eosinophilic dermatitis. Numerous microfilariae were in the dermis, but there was no consistent relationship between the presence of microfilariae and the severity of the inflammatory reaction. In all 40 horses, skin snips taken 4 to 33 days after treatment were negative for microfilariae, and a marked clinical improvement occurred 2 to 3 weeks after treatment, when the lesion was replaced by healthy skin and new hair. Twenty-four hours after treatment, an edematous reaction occurred on the lower portion of the abdomen of 4 (10%) horses and within the area of the lesion in 6 (15% horses). The reactions disappeared within 24 to 72 hours, irrespective of whether horses were treated with corticosteroids. When further skin samples were taken from 15 horses 4 to 9 months later, 9 of them were free of microfilariae and the 6 others had only low counts (17 to 97). An additional 7 infected horses, treated when there was little chance of reinfection (November to December 1981), were all free of microfilariae at 6 to 10 days and 4 to 5 months after treatment. The marked clinical improvement in all horses after disappearance of microfilariae from the dermis indicates that microfilariae are involved in the cause and pathogenesis of the dermatitis.     

Morphologic and morphometric studies of the intrinsic laryngeal muscles in clinically normal adult dogs

To establish normal histologic and histochemical data and to determine reference values for fiber type proportions (percentages, mean fiber diameters, atrophy and hypertrophy factors, and variability coefficients), a histochemical study was carried out on intrinsic muscles of the larynx (cricothyroid, cricoarytenoid lateralis, cricoarytenoid dorsalis, and thyroarytenoid muscles) of clinically normal dogs. Using myosin adenosine triphosphatase stain under acidic preincubation (pH 4.3) conditions, 3 histochemical fiber types--1, 2A, and 2C--were recognized. The percentage of type-2C fibers varied from 1 to 2% in thyroarytenoid muscles to approximately 10% in cricoarytenoid lateralis muscles. There was no significant difference in mean diameter between left- and right-side specimens of each muscle for type 1 vs type 2. The largest fibers (mean +/- SD) of both types were observed in the cricothyroid muscles (type 1, 38.19 +/- 7.76 microns; type 2, 43.25 +/- 8.66 microns), and the smallest fibers were found in the thyroarytenoid muscles (type 1, 29.38 +/- 5.12 microns; type 2, 33.84 +/- 6.20 microns). Respective mean diameters of fiber types from cricoarytenoid dorsalis (type 1, 32.05 +/- 5.69 microns; type 2, 38.95 +/- 7.75 microns) and cricoarytenoid lateralis (type 1, 33.75 +/- 5.98 microns; type 2, 37.09 +/- 7.01 microns) muscles were similar. The histographic distribution of fiber type diameters was unimodal in all muscles. In each muscle, the mean fiber diameter of type-2 fibers was greater than that of type-1 fibers.(ABSTRACT TRUNCATED AT 250 WORDS)     

The acid phosphatase activity and morphological characteristics of Dipetalonema dracunculoides (Cobbold, 1870) microfilariae

The acid phosphatase activity and some morphological characteristics of Dipetalonema dracunculoides microfilariae are described. Their morphological features are closely related to those of the pathogenic Dirofilaria immitis when Knott's technique is used for the microfilarial diagnosis. The acid phosphatase activity pattern found in Dip. dracunculoides microfilariae is clearly different from those previously described for D. immitis, D. repens and Dip. reconditum.     

Eurasian otter (Lutra lutra), a definitive host for Dirofilaria immitis.

A mature male and a mature female Dirofilaria immitis were found in the right ventricle of the heart of a naturally infected 2-yr-old male Eurasian otter (Lutra lutra) that had died of severe lung congestion at a zoo in South Korea. Both developing embryos and microfilariae were present in the uterus of the female D. immitis. Although circulating microfilariae were not detected in blood or tissue, the Eurasian otter may serve as a definitive host for D. immitis.