Serodiagnostic antibody responses to Psoroptes sp. infestations in bighorn sheep

The antibody responses of bighorn sheep (Ovis canadensis) infected with Psoroptes sp. mites were investigated by enzyme linked immunosorbent assay on western blots of P. cuniculi antigens. Serum from 20 Psoroptes sp.-infested bighorn sheep (O. canadensis mexicana, O. canadensis nelsoni, O. canadensis canadensis) from New Mexico, Nevada, California, and Idaho reacted strongly with mite antigens ranging from 12 to 34 kd. Serum from 35 Psoroptes sp.-free bighorn sheep of unknown tick infestation status and from three Psoroptes sp.-free bighorn sheep infested with Dermacentor hunteri ticks did not react with these antigens. Psoroptes sp.-specific antibody responses were present throughout a 16 mo period in one infected bighorn sheep, but were not detectable 8 mo following successful treatment. These results demonstrate that specific serodiagnosis of Psoroptes sp. infestation is feasible in bighorn sheep and suggest that antibody responses are indicative of current or recent infestation.     

Kinetic ELISA for detection of antibodies to Psoroptes sp. (Acari: Psoroptidae) in bighorn sheep (Ovis canadensis)

A kinetic enzyme-linked immunosorbent assay (ELISA) was developed using antigenic extracts prepared from Psoroptes cuniculi mites and sera from 37 Psoroptes sp.-infested and 43 uninfested bighorn sheep (Ovis canadensis). Serial dilutions of these serum samples, representing 3 bighorn sheep subspecies and 9 geographic areas, gave parallel responses when plotted as log dilution versus log kinetic rate. Therefore, all 80 samples were run at a single dilution (1:100) and positive/negative cutoff values were established as the mean kinetic rate of all negative sera plus either 2, 3, or 4 standard deviations. The resulting ELISA was highly reproducible and accurate with sensitivities and specificities of 100% and 97.7%, 94.6% and 97.7%, and 94.6% and 100%, respectively. This immunoassay will be useful for prospective and retrospective studies assessing the distribution and prevalence of Psoroptes sp. infestations in bighorn sheep.     

Exposure to Psoroptes sp. mites is common among bighorn sheep (Ovis canadensis) populations in California.

Sera (n = 806) from 50 populations of bighorn sheep (Ovis canadensis) in California (USA) were evaluated for antibodies to Psoroptes sp. mites using a kinetic enzyme-linked immunosorbent assay (ELISA). Test values for each sample were determined to be either positive or negative at each of two ELISA cutoff values that provided either 100% sensitivity (low cutoff) or 100% specificity (high cutoff), respectively. One hundred sixty-eight (20.8%) sera were seropositive at the low cutoff value, and 87 (10.8%) of these sera also were seropositive at the high cutoff value. Eleven populations were designated as scabies-suspect and 25 populations were designated as scabies-positive because they had at least one seropositive animal at the low and the high cutoff values, respectively. Based on these results, exposure to Psoroptes sp. mites appeared to be widely distributed among bighorn sheep populations from 1980 to 1990 and infested animals may have been present prior to 1980.     

Control of Psoroptes cuniculi in captive white-tailed deer with ivermectin-treated corn

Psoroptes cuniculi, the ear mite of domestic rabbits, was collected from captive white-tailed deer (Odocoileus virginianus). This is the first report of rabbit ear mite infestations in white-tailed deer in Oklahoma or Texas (USA). In addition to moderate infestations in their ears, two 4-yr-old bucks, two 3-yr-old does, and seven 4-yr-old does showed patchy areas of alopecia along the sides and brisket. Both bucks also had patchy areas of alopecia around the base of antlers. Ear mites were eradicated from all deer except from one doe by providing ivermectin-treated corn to the deer at a rate of 1,000 g (equivalent to 200 mcg/kg of ivermectin)/day/deer for several days. The ear mite infestation in the one doe was eradicated by intramuscularly injection with ivermectin at 400 mcg/kg. After treatment with the ivermectin and eradication of the mites, the alopecia improved and eventually was eliminated. The ivermectin-treated corn also controlled all internal nematode parasites in the deer.     

The efficacy of four avermectins on the synanthropic mite Lepidoglyphus destructor under laboratory conditions

The effect of four avermectins on the population growth of pest mite Lepidoglyphus destructor was tested in laboratory experiments. The avermectins (abamectin, doramectin, emamectin-benzoate and ivermectin) of analytical purity were incorporated into an experimental diet at the same molar concentrations, ranging from 0.16 to 8 nmol/3 g of diet. Using an initial population of 50 mites, the population growth was recorded after 21 days at 85 % relative humidity and 25 °C; 12 repeats were performed per avermectin concentration and control. The diets containing the avermectins successfully suppressed the population growth of L. destructor. The EC(50) recalculated to ng of substance per g of diet showed different suppressive effects of the avermectins: doramectin (181 ng/g diet), abamectin (299 ng/g diet), emamectin-benzoate (812 ng/g diet) and ivermectin (992 ng/g diet). Of the tested avermectins, abamectin is registered for the control of phytophagous mites and ivermectin against parasitic mites, i.e., Psoroptes ovis. Although emamectin-benzoate and ivermectin were less effective on L. destructor, all of the tested avermectins are highly suitable compounds for the control of synanthropic mites.     

Recovery of Trichuris tenuis Chandler, 1930, from camelids (Lama glama and Vicugna vicugna) in Argentina

A survey of whipworms was conducted in llamas and vicu?as in northwestern Argentina. Fecal examinations of a group of 14 llamas (April 1995-March 1996) and 69 vicu?as (November 1996) indicated a high prevalence (usually >50%) of Trichuris sp. in these hosts. Prevalence was highest during July-November 1995 that also coincided with the highest mean fecal egg count. During postmortem examinations of 1 llama and 1 vicu?a, specimens of Trichuris tenuis were recovered from the cecum/large intestine of each camelid. This is the first report of T. tenuis in South America, and the first report in the vicu?a. It is suggested that T. tenuis is the typical whipworm of aboriginal camelids.     

5种杀虫剂对黑粪蚊的毒力及对平菇菌丝生长的影响

[目的]黑粪蚊为食用菌生产中的危险害虫之一,通过杀虫剂的毒力测定和对平菇菌丝生长抑制试验,拟筛选获得理想的黑粪蚊防治杀虫剂。[方法]采用毒饵法测定了5种杀虫剂对黑粪蚊幼虫的室内毒力,并研究各杀虫剂对平菇菌菌丝生长的抑制情况。[结果]20%甲氰菊酯乳油、14%阿维·虫螨腈悬浮剂和20%甲维·吡丙醚悬浮剂对黑粪蚊的校正死亡率达80%以上,对黑粪蚊幼虫均有较好的杀灭效果,而苏云金杆菌（以色列亚种）悬浮剂对黑粪蚊幼虫的杀虫效果不理想。5种杀虫剂对平菇菌丝生长均有一定抑制作用,且农药品种间存在极显著差异,20%甲氰菊酯乳油抑制率最高,高浓度480 mg·L^-1处理的抑制率可达16.85%,14%阿维·虫螨腈悬浮剂的抑制率最低,高浓度140 mg·L^-1处理的抑制率仅为5.83%。[结论]本研究中14%阿维·虫螨腈悬浮剂用于平菇菌中黑粪蚊防治效果最好,研究结果将为食用菌黑粪蚊的药剂防治提供理论指导。     

Ovarian estradiol modulates the stimulatory effect of ovulation-inducing factor (OIF) on pituitary LH secretion in llamas

This study was designed to: 1) characterize the effect of ovulation-inducing factor (OIF) on pituitary LH secretion in ovariectomized (OVX) llamas; and 2) determine the effect of OIF on LH secretion in OVX llamas pretreated with estradiol-17β (E-17β) or estradiol benzoate (EB). In Experiment 1, intact and OVX llamas (n = 5 or 6 per group) were assigned to a two by two factorial design: 1) Intact llamas treated with 1 mL of phosphate buffered saline (PBS); 2) Intact llamas treated with 1 mg of purified OIF; 3) OVX llamas treated with 1 mL of PBS; or 4) OVX llamas treated with 1 mg of purified OIF. In Experiment 2, intact and OVX llamas (n = 5 or 6 per group) were randomly assigned to the following groups: 1) Intact llamas treated with 1 mg of purified OIF; 2) OVX llamas treated with 1.0 mL of PBS; 3) OVX llamas treated with 1.0 mg of purified OIF; 4) OVX llamas primed with E-17β, followed by 1.0 mg of purified OIF. Experiment 3 was similar as described for Experiment 2, except that priming was done with EB. In Experiment 1, animal category by treatment and animal category by treatment by time interactions tended (P = 0.08) to affect LH concentration. The effect of OIF on LH released was partly restored (P < 0.05), to the values observed for the intact OIF-treated females, when OVX llamas were primed with E-17β or BE (Experiments 2 and 3). We concluded that peripheral estradiol concentrations in llamas partially modulates the effect of OIF on pituitary LH secretion; however, other ovarian factor(s) could also participate in this modulatory action.     

兔痒螨和水牛痒螨第二转录间隔区（ITS-2）基因序列分析

为了探讨水牛痒螨株和兔痒螨株的分类地位,采用 PCR 技术扩增了四川水牛痒螨株和四川兔痒螨株的第二内部转录间隔区（ITS-2）基因,并与 GenBank 中注册的 5 个国外痒螨株的同源基因进行了比较。序列分析发现：兔痒螨株和水牛痒螨株的序列长度分别为 277 bp 和 281 bp,两序列间存在多处转换、颠换和缺失。四川水牛痒螨株同四川兔痒螨株间及国外痒螨分离株间的 ITS-2 基因同源性较低（87.1%～88.0％）; 而四川兔痒螨株与国外痒螨分离株的同源性较高（95.5％～100.0％）。用痒螨 ITS-2 基因构建的 MP,NJ,ME 及 UPGM 树中,兔痒螨株和水牛痒螨株在不同的系统树中其位置比较固定,且两者相距均较远。根据痒螨 ITS-2 基因同源性分析和系统树构建结果以及其他已报道的相关证据,作者认为：兔痒螨株和水牛痒螨株可能为痒螨属 Psoroptes 中两个不同的种,兔痒螨分离株为马痒螨 P. equi ;而水牛痒螨株与来自兔、山羊、绵羊和黄牛等痒螨株亲缘关系较远,可能为痒螨属中的另一个独立有效种。     

Pituitary response to repeated copulation and/or gonadotropin-releasing hormone administration in llamas and alpacas.

The response of the pituitary gland and ovary to repeated copulatory periods and/or gonadotropin-releasing hormone (GnRH, i.v. 1000 micrograms) administration was determined in llamas and alpacas. Eighty adult females (41 llamas and 39 alpacas with ovulatory follicles) were divided into three general groups for each species as follows: copulation (one or two copulations at either 6- or 24-h intervals) GnRH treatment (one or two treatments at either 6- or 24-h intervals), and combined treatment (copulation followed by GnRH treatment, or GnRH followed by copulation at either 6- or 24-h intervals). An additional control (nontreated) group was composed of 4 llamas and 4 alpacas. The first copulation or treatment with GnRH provoked LH release sufficient to cause ovulation in most of the females (alpacas, 89%; llamas, 92%); urinary pregnanediol glucuronide values, used to verify ovulation, were significantly elevated 48 h after copulation and/or GnRH treatment. A second stimulus, copulation or GnRH, provoked no LH response with concentrations similar to those in nontreated controls and in females not ovulating. Llamas and alpacas thus were refractory to a second copulatory or GnRH stimulus with regard to LH release for up to 24 h following an initial ovulatory release of LH.     

Pigment types in sheep, goats, and llamas

Pigment types in various colors of fiber from sheep, goats, and llamas were assayed by a method using high performance liquid chromatography. In these three species the black/gray group is due to eumelanin, which is fully intense in all three species. Red phenotypes are due to pheomelanin and fade considerably with age in fiber from sheep and goats, but not in llamas. This phenomenon has implications on the genetic mechanisms used in generating white fiber. Brown phenotypes in sheep are due to eumelanin, in goats these phenotypes are equivocal, and they were not observed in llamas.     

Antigenic characterization of Psoroptes spp. (Acari: Psoroptidae) mites from different hosts

Immunoblotting with defined antigens and antisera revealed extensive and nearly complete antigenic cross-reactivity between Psoroptes spp. mites from a bighorn sheep, a mule deer, a cow, and a rabbit. Antigenic differences were not detected between mites from the sympatric bighorn sheep and mule deer. However, minor antigenic differences between mites from the cow and rabbit suggested that these mites were distinct from each other, as well as from the mites from the bighorn sheep and mule deer. These results are consistent with earlier morphologic studies of these populations of mites and provide additional support for the hypothesis that putative populations and/or species of Psoroptes mites may not be reproductively or ecologically isolated, particularly when their hosts are sympatric.     

Levels of progesterone and changes in prostaglandin F(2alpha) release during luteolysis and early pregnancy in llamas and the effect of treatment with flunixin meglumine

The secretory patterns of progesterone in relation to concentrations of 15-ketodihydro-PGF(2alpha) (PGFM) during the period of luteolysis or of maternal recognition of pregnancy were determined in the blood of llamas mated either with an intact or a vasectomized male. The ability of flunixin meglumine (FM) to postpone luteolysis in non-pregnant llamas was investigated by injecting the drug intravenously every 6 h at a dose of 2.2 mg/kg from days 6 to 12 post-copulation into a group of non-pregnant llamas. A pulsatile pattern of prostaglandin release was recorded during luteolysis in non-pregnant llamas, giving further support to the hypothesis that PGF(2alpha) is the luteolytic agent in llamas. The mean number of peaks per animal rose from 0.3 on day 7 to 3.8 on day 10 and then declined to 1.1 on day 12 with corresponding mean peak amplitude changing from 465 to 1234 and 566 pmol l(-1), respectively. In pregnant llamas, prostaglandin pulsatile release also occurred. The mean number of peaks per animal rose from 0.4 on day 7 to 0.8 on day 10 and then declined to 0.2 on day 11 and 0.6 on day 12, with corresponding mean peak amplitude changing from 494 to 676, 388 and 547 pmol l(-1), respectively. The transient decrease and subsequent recovery in progesterone concentrations was observed to occur in connection with prostaglandin release during early pregnancy. Oestradiol-17beta plasma peak concentrations attained after luteolysis were significantly higher than those recorded in early pregnant animals (around 30 pmol l(-1) and ll pmol l(-1)). Concentrations of PGFM decreased rapidly after the first administration of FM and remained low throughout the first 2 days of treatment. Thereafter, pulsatile release of prostaglandins started, and luteolysis proceeded; but a delay of 1-1.5 days in the progesterone decline was observed. Thus, it might be suggested that a higher dose and/or a more intensive injection schedule is required in llamas than in other ruminants to prevent luteolysis.     

Prevalence of Eimeria macusaniensis (Apicomplexa: Eimeriidae) in midwestern Lama spp

To compare the prevalence of Eimeria macusaniensis among midwestern llamas (Lama glama), alpacas (Lama pacos), and guanacos (Lama guanicoe), feces were obtained from Lama spp. in 10 states between October 1989 and February 1996. Feces were examined by centrifugal flotation in sugar solution (specific gravity--1.28-1.30), and oocysts were quantified by a modified McMaster method. Data were compared by host species and age classifications. Typical oocysts occurred in samples from 28% of 76 herds and 10.4% of 443 animals including 12% of 301 llamas, 7% of 115 alpacas, and 7.4% of 27 guanacos. Prevalence was significantly greater (P = 0.009) in animals < 1 yr of age in comparison to older animals for llams (22.1 v.s. 8.5%) and for all Lama spp. combined (17.1 vs. 8.4%). Fecal oocyst abundance was significantly greater (P = 0.001) in llamas < 1 yr of age in comparison to older llamas (30 vs. 16 oocysts per g of feces). Fecal oocyst intensities did not differ significantly. Prevalence in both age groups of midwestern llamas was greater than previously reported for llamas in the western United States. Prevalence in midwestern alpacas < 1 yr of age was lower than reported for alpacas of similar age in South America, but oocyst intensities were similar. These results indicate that infection with E. macusaniensis is more common in Lama spp. in North America than previously recognized.     

Morphology and location of attached follicular cumulus-oocyte complexes in horses, cattle and llamas

Morphology and location of the attached cumulus-oocyte complex (COC) were studied in slaughter-house ovaries in horses (49 follicles, 9 to 44 mm), cattle (68 follicles, 6 to 18 mm), and llamas (38 follicles, 3 to 14 mm). The expected point of ovulation was marked, using the ovulation fossa in mares and the center of the projecting follicular surface in cattle and llamas. A follicle was dissected from an ovary, and tissue was removed from the follicle until the COC became visible by transillumination. However, most llama follicles protruded prominently from the ovarian surface so that dissection was not required to locate the COC. The COC was more readily recognized from the external follicular surface in mares and llamas than in cattle, primarily because of a dark oocyte. Compact COC's projected into the antrum with a smooth dome-shape in horses. The COC's in cattle were also dome-shaped but were more irregular and a few contained prominent processes. The mean diameter of the isolated follicle was calculated from 3 planes, except that in llamas the follicles were spherical so that the 3 dimensions were identical. The angle between a straight line connecting the expected ovulation site and the opposite pole and a straight line from the ovulation site to the COC was defined as the COC-location angle. This angle was chosen because it is unaltered by size of a sphere (45 degrees for a COC at the equator). The mean (+/-SEM) COC-location angle differed (P < 0.01) among horses (39.9 +/- 3.3), cattle (50.0 +/- 2.5), and llamas (64.8 +/- 2.1). In mares, the locations of the COC's did not differ from equality between follicular hemispheres, but in cattle and llamas the COC's were located with greater frequency (P < 0.05) in the hemisphere containing the expected ovulation site (cattle, 65%; llamas, 91%).     

Effect of ivermectin on activities of cytochrome P450 isoenzymes in mouflon (Ovis musimon) and fallow deer (Dama dama)

Ivermectin is an antiparasitic drug widely used in veterinary and human medicine. We have found earlier that repeated treatments of rats with high doses of this drug led to significant increase of cytochrome P450-dependent 7-methoxyresorufin O-demethylase (MROD) and 7-ethoxyresorufin O-deethylase (EROD) activities in hepatic microsomes. In the present study, the effects of ivermectin on cytochrome P450 (CYP) activities were investigated in mouflon (Ovis musimon) and fallow deer (Dama dama). This study was conducted also to point out general lack of information on both basal levels of CYP enzymes and their inducibilities by veterinary drugs in wild ruminants. Liver microsomes were prepared from control animals, mouflons, after single or repeated (six doses in six consecutive days) treatments with therapeutic doses of ivermectin (0.5 mg kg(-1) of body weight), and fallow deer exposed to repeated doses of ivermectin under the same conditions. Alkyloxyresorufins, testosterone and chlorzoxazone were used as the specific substrate probes of activities of the CYP isoenzymes. A single therapeutic dose of ivermectin significantly induced (300-400% of the control group) the activities of all alkyloxyresorufin dealkylases tested in mouflon liver microsomes. Repeated doses of ivermectin also caused an increase of these activities, but due to fair inter-individual differences, this increase was not significant. The administration of ivermectin led to an induction (170-210% of the control) of the testosterone 6beta- and 16alpha-hydroxylase activities in mouflon liver but no significant modulation of chlorzoxazone hydroxylase (CZXOH) activity was found in mouflon liver. CYP-dependent activities in hepatic microsomes were generally higher in fallow deer than in mouflons. However, with the exception of slight increase in the 7-benzyloxyresorufin O-dealkylase (BROD) activities, no significant modulation of the other activities was observed. The induction of CYP3A-like isoenzyme was confirmed by immunoblotting only in the microsomes from mouflons administered with repeated doses of ivermectin; however, no significant increase of CYP1A isoenzymes was observed due to a weak cross-reactivity of anti-rat CYP1A1/2 polyclonal antibodies used in the study. The results indicate that ivermectin should be considered as an inducer of several cytochrome P450 isoenzymes, including CYP1A, 2B and 3A subfamilies, in mouflons. The comparison of induction effect of ivermectin in rat, mouflon and fallow deer also demonstrates the inter-species differences in inducibility of CYP enzymes.     

Infection of llamas with stored Eimeria macusaniensis oocysts obtained from guanaco and alpaca feces

Oocysts obtained from a guanaco and an alpaca with natural infections were identified as Eimeria macusaniensis and evaluated for host specificity and infectivity over time. In 3 separate trials conducted over 4 yr, 4 adult llamas were fed 500-5,000 sporulated oocysts obtained from guanaco feces stored under laboratory conditions for 41-84 mo. Infections with prepatent periods of 36-41 days and patent periods of 38-55 days developed in 4/4 llamas. In a fourth trial, 3 adult llamas and 1 alpaca were each fed 1,000 sporulated E. macusaniensis oocysts obtained from alpaca feces stored in the laboratory for 3 mo. Infections with prepatent periods of 33-34 days and patent periods of 14-20 days developed in 3/3 llamas. Infection in the alpaca had a prepatent period of 58 days and a patent period of 1 day. Clinical signs associated with infection, if any, were minimal and included increased fecal mucus and occasional soft feces. These results provide evidence that E. macusaniensis is a single species transmissible amongst alpacas, llamas, and guanacos and that oocysts of this species can remain infective for many years.     

Effects of lactational and reproductive status on ovarian follicular waves in llamas (Lama glama)

The effects of lactational status and reproductive status on patterns of follicle growth and regression were studied in 41 llamas. Animals were examined daily by transrectal ultrasonography for at least 30 days. The presence or absence of a corpus luteum and the diameter of the largest and second largest follicle in each ovary were recorded. Llamas were categorized as lactating (N = 16) or non-lactating (N = 25) and randomly allotted to the following groups (reproductive status): (1) unmated (anovulatory group, N = 14), (2) mated by a vasectomized male (ovulatory non-pregnant group, N = 12), (3) mated by an intact male and confirmed pregnant (pregnant group, N = 15). Ovulation occurred on the 2nd day after mating with a vasectomized or intact male in 26/27 (96%) ovulating llamas. Interval from mating to ovulation (2.0 +/- 0.1 days) and growth rate of the preovulatory follicle (0.8 +/- 0.2 mm/day) were not affected by lactational status or the type of mating (vasectomized vs intact male). Waves of follicular activity were indicated by periodic increases in the number of follicles detected and an associated emergence of a dominant follicle that grew to greater than or equal to 7 mm. There was an inverse relationship (r = -0.2; P = 0.002) between the number of follicles detected and the diameter of the largest follicle. Successive dominant follicles emerged at intervals of 19.8 +/- 0.7 days in unmated and vasectomy-mated llamas and 14.8 +/- 0.6 days in pregnant llamas (P = 0.001). Lactation was associated with an interwave interval that was shortened by 2.5 +/- 0.05 days averaged over all groups (P = 0.03). Maximum diameter of anovulatory dominant follicles ranged from 9 to 16 mm and was greater (P less than 0.05) for non-pregnant llamas (anovulatory group, 12.1 +/- 0.4 mm; ovulatory group, 11.5 +/- 0.2 mm) than for pregnant llamas (9.7 +/- 0.2 mm). In addition, lactation was associated with smaller (P less than 0.05) maximum diameter of dominant follicles averaged over all reproductive statuses (10.4 +/- 0.2 vs 11.7 +/- 0.3 mm). The corpus luteum was maintained for a mean of 10 days after ovulation in non-pregnant llamas and to the end of the observational period in pregnant llamas. The presence (ovulatory non-pregnant group) and persistence (pregnant group) of a corpus luteum was associated with a depression in the number of follicles detected and reduced prominence of dominant follicles (anovulatory group greater than ovulatory non-pregnant group greater than pregnant group).(ABSTRACT TRUNCATED AT 400 WORDS)     

Clinico-pathological findings and cerebrospinal fluid analysis in llamas (<Emphasis Type="Italic">Lama glama</Emphasis>) experimentally infected with the meningeal worm <Emphasis Type="Italic">Parelaphostrongylus tenuis</Emphasis>

In this study, the clinical progression of experimental infection of llamas ( Lama glama) with Parelaphostrongylus tenuis is described. The onset and characterization of neurologic deficits and changes in the hematology, serum biochemical, and cerebrospinal fluid (CSF) in affected llamas are compared before and after appearance of clinical signs. Sixteen apparently healthy, male llamas (median age; 12 months) were used. Five llamas were maintained as uninfected controls, and five, three, and three llamas were orally inoculated with five, ten, and 25 third-stage larvae (L3) of P. tenuis, respectively. The onset, degree, and characterization of neurologic deficits were recorded. Hematology, serum biochemistry, and CSF were analyzed before exposure (Pre) and after neurologic signs appeared (Post). Necropsy and worm recovery from the central nervous system (CNS) were also carried out to confirm infection. Exposure of llamas to 25 L3 of P. tenuis orally resulted in consistent infection and development of disease. Overall, ten of the 11 animals exposed to P. tenuis L3 developed varying degrees of neurologic signs between 45 and 82 days post-exposure (dpe). P. tenuis was recovered from the CNS of seven of the 11 exposed llamas. Neurologic signs progressed from ataxia to paresis, and eventually paralysis. In the hematologic and serum biochemical analyses, only eosinophil count was significantly elevated in the post-exposure samples in the infected groups. Protein was significantly elevated and Pandy test was positive in CSF of infected llamas. This study comprehensively describes the clinical progression of P. tenuis infection in llamas that will prove helpful in future studies to investigate the possibilities of developing antemortem diagnostic tests and new therapeutic programs.     

Evaluation of ivermectin for treatment of hair loss syndrome in black-tailed deer

Since 1997, numerous Columbian black-tailed deer (Odocoileus hemionus columbianus) in western Washington (USA) have developed a hair loss syndrome that often preceded emaciation, debilitation, pneumonia, and death. To study this syndrome, eight affected free-ranging Columbian black-tailed deer fawns were captured from western Washington in February 1999 to determine the effect of ivermectin treatment. Fecal examinations indicated that the internal parasites were Dictyocaulus viviparus, Parelaphostrongylus sp., Trichuris sp., Moniezia sp., Eimeria spp., and gastrointestinal strongyles. Biting lice (Tricholipeurus parallelus) were observed on all deer, with up to 5 lice/cm(2) on the index areas counted. Three deer were treated with ivermectin subcutaneously at doses between 0.2 and 1.3 mg/kg of body weight monthly for four consecutive months, and five control deer received no anthelmintic treatment. Complete blood counts, parasite evaluations, weight gains, and hair loss evaluations were used to assess effectiveness of treatment. Two untreated deer died during the experiment compared with no deaths among the three treated deer. Treated deer gained significantly more weight (P<0.05) than the untreated deer (22.4 vs. 12.6 kg, respectively) that survived the experiment, had significantly fewer parasite eggs and larvae (P<0.05) in feces and significantly fewer nematodes (P<0.05) at necropsy, and regrew their hair at a faster rate than untreated deer. Lice and all nematode eggs and larval stages in feces were eliminated or greatly reduced following treatment. On the basis of these data, excessive louse populations, gastrointestinal nematodes, and the lung-worms Parelaphostrongylus sp. and D. viviparus, might be important predisposing factors for this hair loss condition and death of affected animals.