Experimental infection with Ancylostoma caninum larvae in mice. IV. Serum protein pattern during primary infection.

Serum protein of Swiss albino mice infected with Ancylostoma caninum larvae, were analysed electrophoretically. Twenty mice were infected with a dose of 1000 larvae and the alterations in serum protein during an infection period of 30 days were recorded and compared with uninfected controls. The result showed a significant decrease in albumin and gamma globulin with an increase in beta globulin. There were no significant changes in the alpha-1 and alpha-2 globulins. The total globulins increased and A/G ratio decreased. These changes appeared to be remarkable on the 9th day after infection.     

Experimental infection of Nematospiroides dubius in Swiss albino mice. VII. Worm burdens and serum protein fractions

The paper deals with the alterations in serum protein profiles and its possible correlation with the worm burden in Swiss white mice infected with single and repeated doses of N. dubius infective larvae. Marked changes observed in serum protein fractions in all the groups were found to be further raised with increase in dose levels. However, maximum (optimal) changes of different fractions depend on the total number of larvae inoculated irrespective of the number of inoculations given. Percentage of worm retention was found to be inversely proportional to the number of larvae inoculated. Worm expulsion during repeated infections was attributed to the therefore, participation of increased amount of immunoglobulins and, humoral immunity (immediate type) has been suggested to play a major role in the immune mechanism of this model.     

Immune response of guinea-pigs to chemically abbreviated prepatent Metastrongylus apri infection.

The effect of chemical abbreviation of the primary infection dose (PID) of 160 infective larvae of Metastrongylus apri on the immune status of the guinea-pig host was studied. The criteria used for assessing the status of immunity consisted of clinical manifestations following administration of a challenge infection dose (CID) of 800 infective larvae of M. apri, the rate of worm recovery 15 days post-CID and the rate of mortality following administration of CID. Among the guinea-pigs of the main experimental group, where 15-day-old PID was abbreviated by two parenteral doses of levamisole, a strong immunity to CID given 35 days post-PID was built-up. Against this, all the guinea-pigs of a control group, which did not receive PID, died between 16 and 22 days post-CID. The increase in serum gamma-globulin level of the guinea-pigs, where the PID was abbreviated chemically, suggested that the rise of this globulin fraction in the serum could be in some way related to the resistant state of guinea-pigs.     

Experimental infection of Nematospiroides dubius in Swiss albino mice. IX. Effect of dose break up on the serum protein patterns

The present study concerns with the effects of larval inoculation with either a single dose or two or more spaced doses of 200 larvae on the serum protein profiles. No significant difference occurred in the various fractions among the three groups indicating that the total quantity of antigenic stimulation in the most important factor in eliciting such changes, no matter whether the dose is given once or spaced in two or three small doses. Serum protein fractions of Swiss albino mice undergoing experimental infection of Nematospiroides dubius do not tend to rise further due to repeated exposures in comparison to those that received a challenge dose only (1). Hence, experiments were designed to ascertain whether there is any difference in serum protein patterns due to breaking up of the infective dose into two or three spaced doses of N. dubius larvae.     

Serum protein profile of mice during infection with of Ancylostoma caninum and after the administration of tetramisole and levamisole

Serum protein changes in mice following Ancylostoma caninum larval infection were observed as decrease in albumin, gamma globulin and increase in beta globulin. These serum protein components showed a tendency to return back to their normal levels after the administration of effective anthelmintic such as tetramisole or levamisole to the infected mice. The increased level of beta globulin after treatment although decreased but did not return to its normal level within 14 days observation period.     

The effect of Trichinella spiralis on muscular activity of experimentally infected mice

Nematodes of genus Trichinella are wide-spread zoonotic parasites, able to infect a large variety of vertebrates. Animal hosts are usually regarded as asymptomatic carriers. However, there is little data regarding the functional consequences that T. spiralis infection renders on muscle cells. The aim of the present study was to assess the effect of T. spiralis on the effort capacity of experimentally infected mice. Overall, 60 mice, divided into three groups were used: M (uninfected), L200 and L1000, infected with 200 or 1000 larvae/mouse respectively. The mice were periodically weighed and their effort capacity was evaluated (days 0, 7, 15, 35 and 60). From each group, two randomly selected mice were euthanized after evaluation carcasses were artificially digested in order to establish the number of larvae per gram (LPG). On day 0, there were no significant differences among groups. Starting with day 7, the effort capacity of infected groups decreased, with significant differences between group M and the infected groups. From day 15, the differences between the infected groups also became significant. The LPG gradually increased and the differences between groups were always significant. A strong correlation between the LPG and decreased effort capacity was noted. The present study demonstrates the reduction of muscular capacity in mice experimentally infected with Trichinella spiralis, in correlation with the infective dose, providing new insights in this parasite's transmission strategy.     

Resistance to ivermectin by Haemonchus contortus in goats and calves.

Efficacy of ivermectin on susceptible or resistant populations of the parasitic nematode Haemonchus contortus was determined in cattle and goats held in a barn. Goats were each infected with 3000 infective, ivermectin-susceptible or -resistant H. contortus larvae on day 0 and reinfected with 2000 infective larvae on day 24. Goats were treated orally with 600 micrograms kg-1 ivermectin on day 31. No significant differences were detected in blood packed cell volume (PCV) or total protein (TP), prepatent period, or epg among the four groups of goats that were each infected with one of four parasite strains (one susceptible, three resistant). There were no differences among the four parasite strains in the numbers of infective larvae that developed to the third larval stage from fecal cultures or in the viability of cultured infective larvae when held in the laboratory at 27 +/- 1 degrees C for 14 weeks. After treatment with ivermectin, there were significant differences among the parasite strains in PCV, TP, and epg. Total worm counts were reduced by 94 to 97% with three times the recommended dose. Immature and adult Skrjabinema ovis were also present in two treated goats. In a second test, one goat infected once with 10,000 infective larvae of a resistant strain of H. contortus and then treated with nine doses of ivermectin, increasing from 500 to 2000 micrograms kg-1 over a period of 133 days, had 35 adult worms at necropsy. In a third test, three calves were readily infected with an ivermectin-resistant strain of H. contortus from goats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of primary infection on the population dynamics of Nematospiroides dubius after challenge infections in mice

Dobson C., Sitepu P. and Brindley P. J. 1985. Influence of primary infection on the population dynamics of Nematospiroides dubius after challenge infections in mice. International Journal for Parasitology15: 353–359. Similar proportions of the inoculum of Nematospiroides dubius larvae reached sexual maturity by 14 days after administration of 50–400 larvae but more adult worms had been expelled by day 63 after infection from those mice infected with 50 vs 400 larvae. There was a significant correlation between time and worm expulsion for all inoculum size groups except for mice given 400 larvae.In mice reinfected with 100 larvae, after termination of primary infections derived from 10 through 400 larvae, more worms from the challenging dose were recovered from mice given greater compared with those given smaller numbers of larvae at primary infection. The N. dubius population size after challenge infection was correlated positively both with number of larvae administered as the primary infection and with the resultant population size during that infection. The serum anti-N. dubius antibody titres after reinfection were higher in mice given 400 compared with those given fewer larvae at primary infection, and the fecundity and female to male sex ratio of the N. dubius populations decreased in proportion to these antibody titres.Protective immunity against challenge N. dubius infection, in mice which had been drenched free of adult worms established from 400 larvae for 5 down to 1 weeks before reinfection, increased from 45% (1 week) to 80% (5 weeks). There was a negative correlation between the population size of N. dubius during challenge infection and the duration between anthelmintic treatment and challenge infection.     

Effect of egg dosage and host genotype on liver trapping in murine larval toxocariasis

In this study we examined the effect of various initial sensitizing doses of infective Toxocara canis eggs and the effect of murine host genotype on the level of trapping of larvae in the liver after larval challenge. In the initial experiments, C57BL/6J mice were infected with a sensitization dose of 5, 25, 75, 125, or 250 infective T. canis eggs on day 0 postinfection (PI). On day 28 PI all mice were challenged with 500 infective eggs. On days 7, 14, and 21 postchallenge (PC) larval numbers within individual livers were determined. Trapping of larvae was observed in mice receiving a sensitization dose of 25 or more eggs. At 7 and 14 days PC the level of trapping increased with sensitization egg dose up to a dose of 125 eggs. At 21 days PC the level of trapping reached a plateau at a sensitization dose of 75 eggs. The peak level of larval trapping was observed on day 7 and day 14 PC following sensitization doses of 125 and 250 eggs, respectively. In the subsequent experiments, mice of various strains and H-2 haplotypes were inoculated with an initial sensitization dose of 125 eggs and a challenge dose of 500 eggs on day 0 and day 28 PI, respectively. Larval trapping within the liver was determined on day 14 PC. C57BL/6J mice trapped significantly more larvae than DBA/2J mice (P less than 0.01); all other strains trapped larvae at a lower, but statistically similar, level to the C57BL6/J mice.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antigen-specific lymphocyte proliferative responses in inbred mice after Trichinella spiralis infection.

The in vitro antigen-specific lymphoproliferative response of spleen, mesenteric lymph node (MLN), and coeliac lymph node (CLN) cells taken from various strains of inbred mice infected with Trichinella spiralis was assessed. In most experiments cell populations were stimulated with excretory/secretory antigens (ESA) derived from adult and larval worms. Lymphoid cells collected 5-7 days postinfection were usually the most responsive to ESA as measured by [3H]thymidine uptake. Spleen cells were more responsive than either MLN or CLN cells. There was a correlation between in vitro ESA stimulation and worm rejection in strong- and weak-responder strains of mice. Spleen and MLN cells of NFS mice showed higher antigen-specific responsiveness, whereas the same cells from B10.BR (H-2k) and B10.Q (H-2q) strains of mice were less responsive. Among intermediate responder strains 2 patterns were observed. Spleen and MLN cells of BuB and DBA/1 mice responded more strongly than those of C3H mice. Dose-response experiments demonstrated that increasing the infective dose of larvae to the host usually increased subsequent in vitro antigen-specific lymphoproliferation. Furthermore, non-MHC-linked genes appear to be the primary determinant of antigen-specific T-cell-proliferative responses in inbred mice infected with T. spiralis.     

核型多角体病毒与侧沟茧蜂对斜纹夜蛾幼虫的协同作用

研究了斜纹夜蛾幼虫体内的斜纹夜蛾侧沟茧蜂存活率、发育历期、寄主感染病毒时间、病毒浓度之间的关系,并测定了斜纹夜蛾侧沟茧蜂的传毒效率．结果表明,病毒对寄主体内寄生蜂历期无明显影响,寄生在幼虫体内的寄生蜂能在寄主病死前完成发育,存活比例因寄主感染病毒的时间和浓度而异．斜纹夜蛾被寄生后接种病毒(SINPV),距离寄生时间越长,饲毒浓度越低,寄生蜂完成发育的比例越大,但饲毒时间是主要影响因素．从感病幼虫体内发育成的侧沟茧蜂或曾经在感病寄主上产过卵的寄生蜂,以及通过人工方式使产卵器被病毒污染的寄生蜂,均能携带一定数量的病毒．通过产卵活动,侧沟茧蜂成蜂能在寄主幼虫个体间传递病毒．当寄生蜂在感病的寄主幼虫上产卵带毒后,平均可传递病毒给2．14头幼虫;发育于感病幼虫体内的寄生蜂,平均可传递病毒给2．45头幼虫．通过用病毒液浸茧或用混有病毒的蜂蜜饲喂成蜂等方式使产卵器污染病毒的寄生蜂,传毒效率随饲毒浓度增加而提高,平均可传递病毒1．45头和0．94头幼虫     

Heligmosomoides polygyrus: Simple recovery of post-infective larvae from mouse intestines

Mice infected orally with third-stage larvae of Heligmosomoides polygyrus were killed at various times after infection. Their small intestines were removed, tied at each end and incubated at 37 C in dilute culture medium. When intestines were taken from mice infected for a period of between 1 and 7 days, a number of developing larvae comprising up to 20% of the infective dose emerged within 60 min through the intestinal wall into the medium. The recovery of emergent larvae was highest using intestines from mice infected 36 to 120 hr previously. The proportion of parasites emerging from the intestines of 48-hr-infected mice was similar for doses of 100 to 2400 larvae. Significantly fewer larvae emerged from the intestines of mice resistant to reinfection and challenged with third-stage larvae 36–72 hr before necropsy.     

Comparison of immune response in Swiss albino mice due to single and repeated doses of infective Ancylostoma caninum larvae after subcutaneous inoculation

Migratory behaviour of Ancylostoma caninum larvae and host responses were studied in four groups of Swiss albino mice infected subcutaneously with single doses of 1,000, 2,000 and multiple doses of 500 + 500, 500 + 500 + 1,000. After the 1st day most of the larvae found in muscles in all the groups. There is no significant difference in the migratory behaviour and/or the adoptive pattern of larvae in both the singly and multiply infected animals.     

Relationship between three intensity levels of Toxocara canis larvae in the brain and effects on exploration, anxiety, learning and memory in the murine host

Outbred LACA mice were administered low (100 ova), medium (1000 ova), high (3000 ova) and trickle (4x250 ova) doses of Toxocara canis ova and the effect of infection was examined with respect to the number of larvae recovered from the brain and their behaviour. Recovery of larvae from the brain was generally low with the % recovery expressed in terms of the total dose administered being highest for the 3000 dose (6.1%) and 1000 dose (6%), followed by the 100 (4.4%) and trickle (3.5%) doses. The variation in larval recoveries was large between individual mice receiving similar doses. The level of infection in the brain was lower in mice receiving a multiple as opposed to an equivalent single dose of ova. Mice were then divided into three larval intensity groupings based upon the number of larvae recovered from their brain. The ranges for the groups were as follows: low intensity group, 0-15 larvae; moderate intensity group, 27-55 larvae; high intensity group, 66-557 larvae. Three behavioural tests were carried out on control and infected mice. Exploration and response to novelty was examined using a 'T' maze and learning was investigated by means of a water-finding task. Anxiety was measured using an elevated plus maze apparatus. Infected mice were less explorative and less responsive to novelty in the 'T' maze and this was particularly pronounced for the heavily infected mice. In the elevated plus maze, infected mice displayed reduced levels of anxiety to aversive and exposed areas of the maze, particularly in the case of the moderate and high intensity mice. There was evidence for impaired learning ability in the water task apparatus for moderate and high intensity mice. In general, the effects of infection on behaviour were more pronounced in the moderate and high intensity groups compared to the low intensity group.     

Studies on the chemoprophylaxis of subperiodic Brugia malayi infection in the leaf monkey (Presbytis melalophos) with diethylcarbamazine citrate

The chemoprophylactic use of diethylcarbamazine citrate at total oral doses of 15--180 mg/kg body weight was tested against subperiodic Brugia malayi infection in the leaf monkey (Presbytis melalophos). A total dose of 45 mg/kg body weight given over 9 days killed all developing infective larvae. Similarly, a total dose of 35 mg/kg body weight given over 7 days killed all fourth stage larvae. The minimum effective dose that prevents infection would be 5 mg/kg body weight daily for 7 days every month.     

Vaccination of young lambs against infection with Nematodirus battus using gamma irradiated larvae

Helminthologically naIve 6-week-old Suffolk lambs were given 1-3 doses of 20000 gamma-irradiated infective larvae (L3) of the nematode Nematodirus battus at weekly intervals. Following an anthelmintic drench they were challenged with 50000 viable L3 at 10 weeks of age. Nematode worm burdens 14 days post-challenge showed a significant (P<0.01) 66% reduction in the single vaccine dose group. The two and three dose groups had mean worm burdens which were 30 and 42% lower than controls, respectively, although these were not statistically significant. There was little measurable stimulation of the immune system in the vaccinated lambs, suggesting that the repeatedly dosed animals may have developed immunological unresponsiveness to the parasite.     

The effect of Brugia pahangi infection on survival of susceptible and refractory species of the Aedes scutellaris complex

Life table statistics were used to examine the survival functions of filarial susceptible and refractory species of the Aedes scutellaris (Walker) group of mosquitoes, following infection with high and moderate doses of Brugia pahangi (Buckley & Edeson). Survivorship curves and hazard function curves were generated, and the median survival times and the proportions of mosquitoes surviving beyond the extrinsic incubation period of the parasite were determined. In the susceptible populations of Aedes polynesiensis Marks, Ae. pseudoscutellaris (Theobald) and Ae.tabu Ramalingam & Belkin a dose-response relationship was detected between parasite load and mortality. This relationship was characterized by a significant reduction in the proportions of infected female mosquitoes surviving at days 1 and 9 postinfection, reduction in the median survival times and an increase in the hazard rates as the infectious dose increased. The survival of the refractory species, Ae.alcasidi Huang and Ae.katherinensis Woodhill was not significantly affected by the infection. A positive correlation between microfilaraemia in the vertebrate host and parasite load in the susceptible mosquito populations was also observed. Regression analysis of the number of parasites recovered from susceptible mosquitoes at the time of death showed that mosquitoes at highest risk of dying harboured from 11.6 to 19.4 infective larvae when fed on a gerbil with sixty-five microfilariae per 20 microliters blood; this resulted in 34.4-40.2% mortality by day 9 postinfection. A mean number of 32.6-46.9 infective larvae was observed when these populations were exposed to a gerbil with a microfilaraemia of 150 mf/20 microliters and resulted in 72.8% to 80% mortality in these populations. Viable infective larvae were recovered from infected mosquitoes up to 50 days postinfection.     

H.pylori抗体鸡蛋制品对H.pylori感染BALB/c小鼠的实验研究

目的通过幽门螺杆菌(Helicobacter pylori,H.pylori)标准株的接种,建立BALB/c小鼠感染H.pylori胃炎动物模型,评价H.pylori抗体鸡蛋制品对小鼠感染性胃炎的预防效果。方法将灭活的H.pylori国际标准菌株(NCTC 11637)作为抗原,对产蛋鸡进行免疫。免疫后收集鸡蛋,对达到效价的鸡蛋,无菌采集卵黄。BALB/c小鼠60只,适应性喂养1周后,随机分为5组,Ⅰ组为胃炎模型组,Ⅱ组为生理盐水组,Ⅲ、IV、V组分别为低剂量、中剂量和高剂量卵黄抗体组,每组12只。Ⅰ组予H.pylori菌液灌胃造模,Ⅱ组先予生理盐水灌胃后再予H.pylori菌液灌胃对照,Ⅲ、IV、V组分别用不同剂量抗H.pylori卵黄抗体灌胃后再予H.pylori菌液灌胃造模。小鼠均于距最后一次灌胃后8周全部处死,用微需氧细菌培养检测H.pylori定植;HE染色观察小鼠胃黏膜病理组织学改变。结果在接种H.pylori后第8周,Ⅰ组和Ⅱ组小鼠胃内均有大量H.pylori定植,感染率为91.7%,Ⅲ组的感染率是58.3%,IV和V组的感染率均小于30%。结论 H.pylori抗体鸡蛋制品可以抑制BALB/c小鼠感染H.pylori,抗体的保护作用与抗体的剂量呈正相关。     

Effects of Trichinella spiralis on survival,total mass,and organ mass of oldfield mice (Peromyscus polionotus)

Trichinella spiralis is a parasitic nematode that infects many mammals, including humans. Hosts may experience significant physiological changes or may die because of acute inflammatory immune responses toward the parasite. In this study, oldfield mice (Peromyscus polionotus) were used as a new experimental host for T. spiralis. Males of P. polionotus were infected with increasing doses of T. spiralis to determine the effect infection had on survival, mass change, total mass, and relative organ masses. Total juvenile worm burden increased in an asymptotic fashion with infective dose. Large doses (> or = 600 juveniles) significantly reduced survival. There were significant negative correlations between infection intensity (log10[juveniles]/g) and both mass gain and final total mass. Infection had no effect on liver or spleen size. But there were significant negative correlations between T. spiralis intensity and both testis and seminal vesicle masses. These effects on male size and reproductive organs may help explain behavioral changes, such as the elimination of male dominance, seen in previous studies on mice infected with T. spiralis.     

Selected clinicopathologic changes associated with experimentally induced Fascioloides magna infection in white-tailed deer.

Six white-tailed deer (Odocoileus virginianus), less than one year of age, were divided into two groups of three each and administered 50, or 500 metacercariae of ascioloides magna. All six deer became infected. Three additional deer of the same age were uninoculated controls. All deer were monitored for up to 43 weeks after inoculation to investigate changes in weight, selected hematologic values, and blood chemistry values. Although clinical disease was not evident in the infected deer, a significant reduction (p less than .01) in hemoglobin and packed cell volume was detected throughout the experiment. A significant elevation (p less than .01) in the total serum protein level was detected in both infected groups from 0 to 5 months after inoculation. Increases were present in the beta and gamma globulin fractions. No differences (p greater than .05) were detected in the serum calcium, magnesium, or phosphorus levels, or in body weights between infected and uninfected control groups.