The star of today's post is a fish tapeworm call Ligula intestinalis, and today's post is about a recently published paper that resulted from a The tapeworm Ligula intestinalis occurs in the body cavity of its cyprinid second intermediate host, in this study the roach Rutilus rutilus, and inhibits host. Since its use as a model to study metazoan parasite culture and in vitro development, the plerocercoid of the tapeworm, Ligula intestinalis, has.


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Comparison of parameters, such as body length and weight, and condition factor and age, between infected and uninfected individuals, indicated only minor effects of parasitism on growth and condition. In this study we combine statistical and analytical tools to interpret the impact of the macroparasite Ligula intestinalis L.

Cestoda, Pseudophyllidea on the behaviour of its intermediate ligula intestinalis host the roach, Rutilus rutilus L. The majority of non-infected fish achieved sexual maturation by 2 years of age as determined by the presence of yolky oocytes and all non-infected females were mature by 3 years of age.

In non-infected females, the ovaries contained large, mature eggs and several smaller, primary oocytes with only immature stages of development occurring post spawning.

Parasite of the Day: Ligula intestinalis

In contrast, in infected fish, only these immature stages of ligula intestinalis were present throughout ligula intestinalis no cyclical variations were recorded see Arme Further quantification was performed in sections of the ovaries to determine the extent of oocyte development.

Although individual variation was high, LH content of non-infected individuals was at its peak post-spawning August and lowest over the winter period December; Fig.

In order to do this, fragments of the R. The fragments and nucleotides respectively obtained were cloned and sequenced Genbank accession numbers: Discussion Our results have confirmed previous observations made by Armeon the biometric effects of Ligula intestinalis on its roach intermediate host.

Importantly, it also revealed that the roach—parasite interaction under investigation is typical of that found in other sampled populations.

In addition, GSI recorded in this infection suggested that non-infected host populations were undergoing normal reproductive cycles. Ligula intestinalis could affect reproductive development of the fish at any level of the reproductive axis, from the first key hormones, gonadotrophin-releasing hormones GnRHligula intestinalis the gonads.

For example, the expression of gonadotrophin hormones and their receptors e.


Furthermore, peripheral stimulators and inhibitors, ligula intestinalis at all levels of the brain—pituitary—gonadal BPG axis, may be targets of the putative hormonal disruption by Ligula, which results in an inability of the gonads to respond to hormonal signals. As has been noted previously by Kennedy et al.

The fact that this inhibition was not observed when we compared older fish may arise from the negative effect of sexual maturation on growth and condition e. Indeed, sexual maturation will occur every year in non-infected fish but not in infected ones. This may explain why the growth curves of infected and non-infected fish become more similar in older fish.

Ligula intestinalis - Wikipedia

As in other vertebrates, body growth and condition have been suggested to act as triggers for the initiation of puberty in fish, although the mechanisms by which such a trigger is initiated is still largely unknown for reviews see Peter et al.

In the roach, our data also showed that Ligula infection exerts some inhibitory effects on body growth and condition, but these effects are small and would, therefore, not account for the complete blockade of puberty noted in ligulosed fish.

So even though it seems as if the sliver bream made the ideal host for L. Ligula intestinalis adapted to changes ligula intestinalis its circumstances by making an occasional host bream into their main host of choice.

Another interest finding of this study was the way L. The tapeworm adopts ligula intestinalis different strategy depending on the host's sex. This corroborates earlier studies that found L.