Ambient temperature, physical activity and aging in the housefly, Musca domestica.

The relative effects of temperature and physical activity on the life span of the adult houseflies are examined. Populations of male and female houseflies were maintained under conditions of high, intermediate and low levels of physical activity at 15°C and at 23°C. At 23°C life spans of different populations vary considerably in correspondence with the levels of physical activity. Life spans are considerably longer in flies undergoing lower physical activity. At 15°C, where physical activity is quite low, there are relatively small differences in life spans of different populations. The life spans of populations with high and intermediate levels of physical activity, following transfer from 15 to 23°C and vice versa during the first half of the mean life span, are intermediate between those kept continuously at 15 or 23°C. The life span of low activity populations are relatively little affected by the transfer between 15 and 23°C as compared to those kept constantly at one of these temperatures. The data suggest that the life span of the housefly is inversely related to physical activity. The effect of ambient temperature on life span is greatly dependent upon the temperature-associated variation in physical activity. Results of this study support the assumptions of the rate of living theory of aging. A possible explanation is provided for the data in previous studies advocating the converse threshold theory of aging.     

Experimental evolutive cycle of Diphyllobothrium erinaceieuropei in Paracyclops fimbriatus, tadpoles of Bufo arenarum and dogs

Experiments were performed in order to develop the life cycle of Diphyllobothrium erinaceieuropei Rudolphi 1819 (Cestoda, Pseudophyllidea) in Paracyclops fimbriatus and Bufo arenarum as intermediate hosts and dogs as definitive hosts. The eggs of Diphyllobothrium erinaceieuropei from faeces of naturally infected dogs were kept refrigered, in water. In order to obtain coracidiums they were incubated at 25 degrees C, and then were placed in a flask which contained Paracyclops fimbriatus. The copepods were observed to be infected with procercoids 12 days after, (mean temperature 22.6 degrees C) and then, ten tadpoles of Bufo arenarum were put into the same flask. The tadpoles were examined 22, 23, 61 and 107 days later, finding plerocercoids in all them (mean temperature 24.9 degrees C). On the 23rd day, 49 plerocercoids were removed from 6 tadpoles and 28 of them were fed to a bitch. On the 107th day, 11 plerocercoids were recovered from a dead tadpole and 3 of them were fed to another bitch. In the faeces of the first bitch there were observed the eggs of Diphyllobothrium erinaceieuropei 22 days post infection (d.p.i.) and part of the strobila 30 d.p.i.. In the faeces of the second bitch the eggs were found 30 d.p.i..     

The effect of chronic lead acetate trihydrate intoxication in Wistar rats on experimental <Emphasis Type="Italic">Ascaris suum</Emphasis> infestation and immunity

Summary  SPF male Wistar rats were exposed for four months to lead acetate trihydrate present in drinking water (100 mg/l) and subsequently infested with 1000 ± 100 infective A. suum eggs. Metabolic activity of phagocytes and proliferative activity of T-lymphocytes were investigated on Day 4 and 8 after A. suum eggs infestation (Day 130 and 134 of lead acetate trihydrate exposition). The results demonstrated that treatment with lead acetate trihydrate led to increased susceptibility to infestation, manifested by increased average number of A. suum larvae in the lungs of exposed rats compared to unexposed ones. Moreover, migration of A. suum larvae on Day 8 was associated with significant increase in index of metabolic activity of phagocytes in unexposed rats in comparison with controls. In contrast, in rats exposed to the lead and infested by A. suum eggs a non-significant increase in the studied immunological parameters was recorded. Significant differences in immunological parameters were observed between unexposed, infested and infested and exposed groups of rats. In the unexposed group of animals Ascaris suum infestation caused a significant increase in the index of metabolic activity of phagocytes and stimulation index of lymphocytes in comparison with lead exposed rats.     

The content of carbohydrates in larval stages of Anisakis simplex (Nematoda, Anisakidae)

Summary The content of carbohydrates in L₃ and L₄ larvae of Anisakis simplex (defined by Rokicki J.) was studied. Glycogen and trehalose were their major reserve sugars. The concentration of saccharides in L₄ larvae was 2–3-times higher than in L₃ larvae. The content of glycogen was 3.68 ± 1.24 mg/g tissue in L₃ larvae and 11.68 ± 1.21 mg/g tissue in L₄ larvae. Trehalose represented 16.17 % of soluble sugars in L₃ larvae and 43.04 % in L₄ larvae. The contents of maltose, higher polymers of glucose (1.5-times) and myoinositol (1.2-times) in L₄ were higher than in L₃ larvae. After starving the L₃ larvae of the parasite for 48 h at 4°C, the contents of trehalose increased 5-fold and that of glycogen by 20 %, while at 37°C the contents of glycogen was ca. 30 % higher and that of trehalose 40 % less than in larvae freshly isolated from the host (p < 0.01). The data obtained during starving the L₃ larvae of A. simplex may be a consequence the role of trehalose as protective compound at stress condition. We suggest that probably in higher temperatures it acts as first a source of energy, and it also might serve to restore the levels of glycogen.     

Changes in trehalase activity and trehalose level during Ascaris suum (Nematoda) embryogenesis

Summary The levels of trehalose and the activity of trehalase during the development of Ascaris suum eggs were investigated. The level of trehalose in the zygote was high (2.96 ± 0.07 mg/g). During cleavage of eggs, it decreased (0.91 ± 0.35 mg/g). A higher concentration of the sugar was recorded at the blastula and during gastrulation, but it did not reach the uncleaved eggs level. In the early motile larvae, the concentration of trehalose was high (4.58 ± 2.01 mg/g). It decreased with development of L₁ larvae (3.10 ± 1.47 mg/g). A rapid increase in trehalose reserves was observed between the L₁ and L₂ stages. The highest content of trehalose was found in invasive L₂ larvae (5.78 ± 1.39 mg/g). The activity of trehalase at the zygote stage was high (560.22 ± 322.31 U/mg). It decreased at the beginning of cleavage. It was the lowest at the 4–6-cell stage (189.76 ± 114.97 U/mg). An increase in the enzyme activity occurred after reaching the blastula stage (348.44 ± 343.34 U/mg). The highest trehalase activity was recorded during the L₁ larvae stage (635.72 ± 251.16 U/mg). The activity of that enzyme was about three times lower in the invasive stage larvae than in the L₁ larvae.     

A comparative study of the ovicidal and larvicidal activities of aqueous and ethanolic extracts of pawpaw seeds Carica papaya (Caricaceae) on Heligmosomoides bakeri

ObjectiveTo assess the ovicidal and larvicidal activities of aqueous and ethanolic extracts of pawpaw seeds Carica papaya (Caricaceae) on the eggs and first stage larvae (L₁) of Heligmosomoides bakeri.MethodsEggs of this parasite were obtained from experimentally infested mice (Mus musculus) and larvae were from eggs after incubation at 25°C for about 72 hours. The eggs and larvae were exposed to ten different concentrations (0.125, 0.25, 0.375, 0.5, 0.75, 1.0, 1.25, 1.75, 2.25 and 2.75 mg/mL) of both aqueous and ethanolic extracts respectively for 72 hours. Distilled water and 0.05% ethanol used as placebo and negative control, respectively.ResultsPlacebo and negative control group all showed average 92% embryonnation, 98% egg hatching and 2% larval mortality, and did not affect development and larval survival. The extracts inhibited embryonic development, egg hatching and larval survival. In general, the ovicidal and larvicidal activities increased with increasing concentration of different extracts. The aqueous extract was found to be more potent on eggs than on larvae. At 2.75 mg/mL, only 8% of eggs embryonnated and 50% hatched to L₁ vs 57% embryonic development and 79% hatching occurred in the ethanolic extract. However, this later extract was more efficient in preventing larval development producing 96% mortality as against 68% with the aqueous extract.ConclusionsThese results shows the ovicidal and larvicidal properties of aqueous and ethanolic pawpaw seeds extracts.     

The infectivity and antigenicity of Toxocara canis eggs can be retained after long-term preservation

Suspensions of fertilized eggs of Toxocara canis were mixed with 2% neutral formalin and preserved at 4 degrees C. When, after storage for 0, 12, 18, 21 and 24 months, samples of the eggs were incubated at 30 degrees C for 12 days, 96.8%, 92.6%, 74.1%, 51.0% and 19.3% of the eggs in the samples were found to embryonate. The embryonated eggs produced from the fertilized eggs preserved (in 2% neutral formalin at 4 degrees C) for 0, 12, 18 and 21 months were then tested for their infectivity to BALB/c mice, each mouse being given 800 embryonated eggs. The numbers of larvae recovered from the mice and the sites from which they were recovered, 2 or 14 days post-infection, appeared unaffected by the length of storage of the eggs. The infected mice all had similar eosinophil counts in their peripheral blood and similar serum titres of Toxocara-specific IgM and IgG antibodies, and cultures of their spleen cells produced similar amounts of interleukin-4, interleukin-5 and interferon-gamma when stimulated with concanavalin A. The results of SDS-PAGE indicated that egg preservation for at least 21 months had no effect on the excretory-secretory antigens in samples of medium from cultures of infective larvae released from the eggs. In summary, at least 50% of the fertilized eggs preserved in 2% neutral formalin at 4 degrees C for 21 months could fully embryonate and then had the same infectivity and antigenicity as embryonated fresh eggs.     

Activity of four entomopathogenic nematode species against different developmental stages of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera, Chrysomelidae)

Summary  Four entomopathogenic nematode species (Steinernema feltiae, S. carpocapsae, Heterorhabditis bacteriophora, and H. megidis) were tested in a laboratory bioassay for the efficacy of these pathogens in controlling the larvae and adults of the Colorado potato beetle, Leptinotarsa decemlineata. The main aim of the study was to develop an efficient sustainable control method against the pest. With this we could develop a strategy of potato production with the intention of diminishing or even preventing the appearance of pest resistance to insecticides. The activity of these biological agents was assessed at three different temperatures (15, 20, and 25 °C) and three concentrations (200, 1000, and 2000 infective juveniles per individual). Mortality of three stages (young and old larvae and adults) was determined 2, 4, and 7 days after treatment. At 15 °C entomopathogenic nematodes showed the lowest efficacy against all insect stages. No significant differences in efficacy was determined at 20 and 25 °C as all nematodes caused prompt death of all stages. At all temperatures young larvae were most susceptible. However, when controlling overwintered adults for the purpose of preventing the mass appearance of Colorado potato beetle, we recommend an application of higher concentrations of S. feltiae suspension.     

广西华支睾吸虫病流行病学调查研究

目的　调查广西华支睾吸虫病的分布范围和流行特点。　方法　根据广西的不同地理位置及行政区划 ,随机选取调查点。用水洗沉淀法或醛醚集卵法粪检华支睾吸虫卵 ,并计算克粪便虫卵数 ;用玻片压碎法、压片法和人工消化法检查中间宿主淡水螺、鱼类的自然感染情况 ;用解剖动物找成虫或粪检查虫卵的方法了解保虫宿主感染情况。　结果　共调查 4 4个县 (市 ) 135个点 112 4 4 4人 ,人群平均感染率为 2 0 .15 % ,感染率随年龄增长而升高 ,男性高于女性 (P<0 .0 1)。第一中间宿主有赤豆螺、纹沼螺、长角函螺和硬豆螺 ;第二中间宿主有麦穗鱼、台细鳊等淡水鱼类 4科 32种。保虫宿主有猫、犬。人群感染方式以吃“鱼生”为主。　结论　广西华支睾吸虫病流行广泛 ,其中南部地区流行程度较重 ,呈“片状”分布 ;北部地区较轻 ,呈“点状”分布。     

广州管圆线虫生活史的实验室构建与观察

目的实验室构建广州管圆线虫生活史,进一步了解其生长变化及其致病性,为广州管圆线虫病的防治提供基础资料。方法福建省采集的广州管圆线虫L3经口、腹腔注射、皮下注射和皮肤接触等途径感染SD大白鼠,观察感染效果。从SD大白鼠粪便中获得广州管圆线虫L1,感染人工繁殖的福建子代福寿螺,25．5～26．5℃条件下,分别置于无水环境和水族环境饲养,观察广州管圆线虫在宿主体内的生长规律、发育进程、分布状况、不同发育期幼虫形态特征及诱导的病理变化等。结果L3经口感染的感染率较其他感染途径为好;无水环境中的福寿螺在休眠状态不影响广州管圆线虫发育;实验室完成一个广州管圆线虫生活史最短为50d;休眠状态螺体L3出现前期为16．5d,水族环境螺L3出现前期为18．5d,鼠粪L1开放前期为33．5d。L3主要分布于感染螺的肺、肌肉及肝脏等处,螺肺囊可出现明显的L2、L3结节病理表现。折光颗粒、头部特征、鞘膜变化是各期幼虫形态特征的主要鉴别指标。观察期感染鼠多数死亡,虫卵诱导的肺纤维化和肺动脉虫栓是主要死因。结论经口感染大白鼠及感染性螺置休眠状态是维持实验室广州管圆线虫生活史较好的方式。广州管圆线虫生活史长短取决于中间宿主及环境温度。螺肺的特殊结构和幼虫结节病理表现为创立新的检测方法奠定了基础。     

福寿螺休眠期体内广州管圆线虫生长发育及其感染性的观察研究

目的 了解福寿螺处于休眠期对其体内感染的广州管圆线虫幼虫生长发育及其感染性的影响。 方法 来自实验室的广州管圆线虫L1幼虫感染福寿螺，感染后第1 天螺置于25.0～25.5 ℃ 恒温室中休眠，观察体内幼虫生长发育情况，第13天起解剖观察幼虫生长发育情况。感染后第20 天福寿螺置冬季室内自然变温条件下休眠2个月，每隔10 d观察螺体内幼虫活力。检获的L3幼虫经口或腹腔注射感染SD大鼠，观察其感染性。同时观察螺的生存与体重变化情况，并以水族缸饲养螺作平行对照。 结果 25.0～25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育，且其幼虫发育历期为（16.3±0.6） d，显著快于水族缸饲养螺（17.6±0.96）d（t=5.72，P<0.01）。冬季室内自然变温条件下的休眠螺，生存率高于水族缸饲养螺（P<0.05),体重下降率为（33.5±4.3）%, 也高于水族缸饲养螺[（9.0±2.3）%, t=10.68， P<0.01]。但随着休眠期的延长其死亡率增高（x²=18.31，P<0.01）。从存活螺体内检获的不同活力的L3幼虫均可感染SD大鼠。 结论 25.0～25.5 ℃ 恒温条件下螺休眠不影响体内幼虫发育，冬季室内自然变温条件下螺休眠或水族缸饲养，其体内幼虫均具有感染性。 感染的福寿螺越冬方式，休眠明显优于水族缸饲养。     

Incompetence of deer as reservoirs of the Lyme disease spirochete

To determine whether deer may serve as reservoir hosts for the Lyme disease spirochete, we sought evidence of infection in nymphal Ixodes dammini derived from larvae that had engorged on white-tailed deer. A total of 19 deer were shot in two Lyme disease foci in Massachusetts during September 1986, the season in which larvae were most abundant. An average of 342 larval ticks of this species were collected from each deer. Of those that developed to the nymphal stage, the gut contents of 185 were examined for Borrelia burgdorferi by a direct fluorescent antibody test. Spirochetes were detected in about 1% of these nymphs, a rate of infection attributable to transovarial transmission. In contrast, infection was detected in 23% of 39 field-swept nymphal ticks of the same cohort that were collected during the following season. Although deer may be infested by numerous larval I. dammini, such ticks appear not to become infected by Lyme disease spirochetes.     

Empirical maximum lifespan of earthworms is twice that of mice

We considered a Gompertzian model for the population dynamics of Eisenia andrei case-cohorts in artificial OECD soil under strictly controlled conditions. The earthworm culture was kept between 18 and 22°C at a constant pH of 5.0. In all, 77 lumbricids were carefully followed for almost 9 years, until the oldest died. The Eisenia median longevity is 4.25 years and the oldest specimen was 8.73 years. Eisenia cocoons were hand-sorted every 3 weeks, washed in distilled water, placed in Petri dishes, and counted. Regular removal did not reduce breeding. Each fertile cocoon contained on average two or three embryos. The failure rates (mortality and infertility percentages) are smooth power functions where the rate at time (n + 1) captured most of the phenomenology of the previous rate at time n, as expected by the considered law, but not at both the beginning and the end of this long-term laboratory study.     

Molecular genotyping of <Emphasis Type="Italic">Anisakis</Emphasis> Dujardin, 1845 (Nematoda: Ascaridoidea: Anisakidae) larvae from marine fish of Balinese and Javanese waters,Indonesia

Summary The genetic identification and distribution of Anisakis larvae in Indonesia is described. 110 Auxis rochei rochei and 45 Decapterus russellii were sampled from fish markets in North (Anturan) and South (Kedonganan) Bali. Nematode larvae from A. rochei rochei, Caesio cuning and Epinephelus areolatus from Kedonganan and from Coryphaena hippurus from Pelabuhan Ratu, South Java, were identified using sequence analysis of the internal transcribed spacers (ITS-1, ITS-2) and 5.8S region of rDNA. The larvae belonged to Anisakis typica with an identical sequence to this species from the spinner dolphin (Stenella longirostris) from Brazil, and to 2 further genotypes that differed from that sequence by 0.24–0.47 %. A. typica occurred in the migratory A. rochei rochei and C. hippurus, while Anisakis sp. 1 and 2 were isolated from the same fish species and the non-migratory C. cuning and E. areolatus. The latter genotype is distinguishable by 4 positions in the ITS-1 region (1.1 %), a genetic distance that indicates the presence of an Indonesian A. typica sibling species. The musculature infection in A. rochei rochei was low (2.5 %), indicating no major risk for the fish consumers. The much higher A. typica infection of fish intermediate hosts in the northern Bali coast is suggested to be dependent on the large dolphin population (nematode final hosts) in the waters off Lovina Beach (North Bali).     

Survival of young and old rats in a cold environment

Young (3–4 months) and old (25 months) rats were housed in 5°C continuously for 3 weeks. Controls of similar ages were maintained at 23°C. Old rats in 5°C had a survival rate of 36%, while old rats in 23°C and young rats in 5°C and 23°C had 100% survival during the same period.     

Hot or cold in anal pain?

In 26 volunteers without anorectal complaints, and in 31 patients with anorectal problems such as hemorrhoidal disease, anal fissure, and proctalgia fugax, baseline resting anal canal pressures were recorded manometrically for 5 minutes at room temperature (23° C). In 16 volunteers (Group A) and 21 patients (group B) anorectal manometry was then performed while the anus was immersed in water at varying temperatures (5° C, 23° C, and 40° C). In ten volunteers (Group A′) and ten patients (Group B′) resting pressures were recorded for an additional 30 minutes following immersion for 5 minutes at 40° C. In all subjects (at leastP<0.01), resting anal canal pressures diminished significantly from baseline after immersion at 40° C, but remained unchanged in all subjects after immersion at 5° C and 23° C. In Group A′, anal canal pressures remained significantly reduced for 15 minutes (P<0.02). In Group B′, significant reduction in resting pressure lasted 30 minutes (P<0.02). Wet heat applied to the anal sphincter apparatus significantly and reproducibly decreased resting anal canal pressures over time, and therefore was likely to benefit patients after anorectal operations and those with anorectal pain.     

Preliminary studies on the zoonotic importance of rodents as a reservoir of toxocariasis from recreation grounds in Wroclaw (Poland)

Summary  Due to their specific biology and behaviour, rodents could play a role as an intermediate, definitive or paratenic host for many helminth species, as well as for species of zoonotic significance such as Toxocara spp. or Echinococcus multilocularis. The aim of our preliminary study was to investigate the nematode fauna of rodents collected from recreation grounds located in the vicinity of Wroclaw, and to determine their role in the transmission of toxocariasis in this area. During a one-year period, 90 individuals belonging to three rodent species, i.e. Apodemus agrarius, A. flavicollis and Myodes glareolus, were collected. The overall prevalence of infection with nematodes amounted to 63.33 ± 10.15 % and differed between hosts. Toxocara spp. larvae were located in livers and brains of A. agrarius (12.9 %). Our results indicate a role of rodents in the circulation of toxocariasis in sub-urban areas, which serve as recreation grounds for the city of Wroclaw.     

Oxidative stress in hepatocytes and stimulatory state of Kupffer cells after reperfusion differ between warm and cold ischemia in rats

Rat liver was kept at 4°C or 37°C in MEM, and reperfused through a closed circulation from the hepatic vein to the portal vein at 37°C with the same solution. Although purine nucleoside phosphorylase and ALT activities were increased in the perfusate, depending on the duration of ischemia at both 4°C and 37°C, the ratio of the latter to the former was significantly higher after 37°C-ischemia than after 4°C-ischemia. The stimulation stage of Kupffer cells evaluated in situ by formazan deposition after liver perfusion with nitro blue tetrazolium and phorbol myristate acetate was elevated after 4°C-ischemia longer than 1 h, but not after 37°C-ischemia. In contrast, the degree of oxidative stress in hepatocytes assessed by formazan deposition after liver perfusion with nitro blue tetrazolium alone was greater after 37°C-ischemia than after 4°C-ischemia. These results suggest that oxidative stress in hepatocytes and the stimulatory state of Kupffer cells after ischemia-reperfusion may differ between 4°C-ischemia and 37°C-ischemia, probably leading to different development of liver damage.     

The influence of desiccation and UV radiation on the development and survival of free-living stages of cyathostomins under field and laboratory conditions

Summary The present work describing both laboratory and field experiments was performed to assess the effects of desiccation and UV radiation on the development and survival of free-living stages of equine cyathostomins. Cyathostomin larvae in horse faeces did not develop to the infective stage when faecal humidity levels dropped below 23 %, nonetheless solitary preinfective larvae were still recovered after 151 days (humidity 19.5 %). The development to infective stage after remoistening occurred for the last time after 54 days following desiccation. Preinfective stages are susceptible to the effects of the direct desiccation stage. The preinfective larvae were rapidly killed within one minute, the cyathostomin eggs within 5 hours. The numerous normal mobile infective larvae were encountered after 35 days of the desiccated period. The preinfective stage of cyathostomins also showed very little tolerance to direct sun radiation: most eggs were killed by the exposure within 3 hours and the preinfective larvae within 1 hour. The survival of infective larvae was, on the other hand, unaffected by sun radiation after 7 days (P < 0.05). However, desiccated infective larvae were then found to be susceptible to UV radiation, resulting in total mortalities after 5 days.     

Biology of Dermacentor marginatus (Acari: Ixodidae) under laboratory conditions

ObjectiveTo investigate and survey the biology of Dermacentor marginatus (D. marginatus) under laboratory conditions.MethodsIn this investigation, D. marginatus adult ticks were collected from sheep in Semnan province. Then various developmental stages of D. marginatus including larvae, nymphs and adult males and females under laboratory condition were bred and their biology was scrutinized.ResultsThe requisite time to complete the life cycle of D. marginatus under controlled laboratory conditions for larvae (26 °C, 75% relative humidity) and nymph (26 °C, 95% relative humidity) moulting, was on average 92 d (range 75–104 d), including preoviposition and egg incubation (22.5 d), larvae incubation (20.5 d), nymphal stage (28 d) along with male maturation (21 d). The index of conversion efficiency and the index of reproduction efficiency in females were 0.397 and 8.300, respectively.ConclusionsAlthough in this investigation, there was no meaningful correlation between preoviposition period and the weight of female ticks which were laid successfully. The significant linear relationship was fully observed between the weight of engorged female of D. marginatus and the number of eggs laid. The mean of preoviposition period from 5.4 d in autumn to 34.2 d in spring increased. The minimum weight of ticks with laying capacity was 69 mg and lighter ticks (21 mg) either did not lay or if they did their eggs did not hatch.