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PubMed1990

IgG response of rats to the excretory-secretory products of Litomosoides carinii.

The nature of antibody responses to the excretory-secretory (ES) products of adult worms and microfilariae (Mf) of Litomosoides carinii in albino rats and their possible role in protection have been studied. Rats were immunized with ES products derived from in vitro incubation of adults or Mf. The sera from these rats promoted neutrophil-mediated killing of Mf in vitro. The antibody responsible for the cytocidal activity was identified as IgG isotype. Indirect fluorescent antibody test showed the presence of IgG on the surface of Mf incubated in either of the immune sera. The immune sera were effective in clearing the circulating Mf in Mastomys natalensis, indicating the protective nature of the antibody. Thus, L. carinii in culture liberate functional antigens that seem to have protective potential.

Animals↗
PubMed1977

[Immunological diagnosis of filariosis in persons returning from tropical countries and in European and indigenous inhabitants of endemic areas (author's transl)].

Serum samples from persons who lived in areas where onchocerciasis occurred or who had filariasis were examined with the complement fixation test and the indirect hemagglutination test for the presence of antibodies against crude extracts from Dirofilaria immitis, Onchocerca volvulus, Dipetalonema viteae, and Ascaris suum. The results could be interpreted as follows: 1. The indirect hemagglutination test was more sensitive than the complement fixation test for the demonstration of antibodies in sera from European and indigenous inhabitants of endemic areas. 2. There were no differences between the responses to the four crude worm extracts among the groups of 21 patients with Loa loa, 12 patients with Onchocerca volvulus, 11 patients with Dipetalonema perstans, and 22 patients with clinical filariasis in whom no microfilaria had been found. It was concluded that the examination with crude extracts cannot give any information about the antigens that had caused the stimulation of antibodies.

Adolescent↗
PubMed1979

[Diaplacental transmission of microfilaria of the species, Brugia pahangi, in the cat].

Eight kittens born of two Brugia pahangi infected cats have been studied for transplacental passed microfilariae. In the peripheral blood microfilariae could not be demonstrated at any time. However, in the lung of a young cat killed two days post partum ca. 30 microfilariae have been found (microfilaremia of the mother 90 mf/20 mm3). Histological studies suggested two possibilities of transplacental passage--by blood and by secretion of the uterus glands.

Animals↗
PubMed1984

Stephanofilarial dermatitis in India.

Four species of Stephanofilaria have been reported from India causing various forms of dermatitis in cattle, buffalo, goat and elephant. However, additional work is needed to establish their identity as separate species. The lesions appear to flare up following reinfection, while the application of a petroleum jelly alone reduces them. In vitro tests have shown organophosphorous compounds to possess stephanofilaricidal action in addition to their insecticidal activity. Aspects where further work is needed are indicated.

Animals↗
PubMed1982

Efficacy of the avermectins against filarial parasites: a short review.

The avermectins are macrocyclic lactones produced by Streptomyces avermitilis. One of them has been chemically modified and given the non-proprietary name ivermectin. The compounds have shown efficacy against various stages of filarial parasites. With respect to pre-adult stages in the mammalian host, activity has been observed against Dirofilaria immitis in ferrets and dogs, and Dipetalonema viteae and Litomosoides carinii in jirds (Meriones); but activity has not been observed against the developing stages of Brugia spp. in jirds or Onchocerca spp. in cattle. The compounds have not shown activity against adult filarial worms, except in the case of Setaria equina in horses and possibly Dipetalonema viteae in jirds. With respect to the first state larva (microfilaria) in the mammalian host, efficacy has been observed against Dirofilaria immitis in dogs, Brugia malayi in multimammate rats (Mastomys), Dipetalonema viteae and Litomosoides carinii in jirds and Onchocerca spp. in horses and cattle; but activity has not been observed against microfilariae of Brugia pahangi in jirds or cats. Efficacy against filarial parasites has been observed following oral or parenteral administration of drug, sometimes at extremely low dosage. For example, a single oral dosage of 0.05 mg/kg was highly active against the third and fourth larval stages and microfilariae of D. immitis in dogs.

Animals↗
PubMed2000

IL-5 is essential for vaccine-induced protection and for resolution of primary infection in murine filariasis.

The pathways conferring immunity to human filariases are not well known, in part because human-pathogenic filariae do not complete a full life cycle in laboratory mice. We have used the only fully permissive infection of mice with filariae, i.e., infection of BALB/c mice with the rodent filarial nematode Litomosoides sigmodontis. Our previous results showed that worm development is inversely correlated with Th2 cytokine production and eosinophilia. The scope of the present study was to directly elucidate the role of interleukin-5 (IL-5) and eosinophils in controlling the development of L. sigmodonitis after vaccination and in primary infection. BALB/c mice immunized with irradiated third-stage larvae (L3) were confirmed to have elevated IL-5 levels as well as high subcutaneous eosinophilia and to attack and reduce incoming larvae within the first 2 days, resulting in 70% reduction of worm load. Treatment of vaccinated mice with anti-IL-5 antibody (TRFK-5) suppressed both blood and tissue eosinophilia and completely abolished protection. This demonstrates, for the first time in a fully permissive filarial infection, that IL-5 is essential for protection induced by irradiated L3 larvae. In contrast, in primary-infected mice, anti-IL-5 treatment did not modify filarial infection within the 1st month, most likely because during primary infection IL-5-dependent mechanisms such as subcutaneous eosinophilia are induced too late to disturb worm establishment. However, there is a role for IL-5 late in primary infection where neutrophil-dependent worm encapsulation is also under the control of IL-5.

Animals↗
PubMed2002

Murine filariasis: interleukin 4 and interleukin 5 lead to containment of different worm developmental stages.

We compared the impact of IL-4 and IL-5 deficiency during the fully permissive infection of BALB/c mice with the rodent filaria Litomosoides sigmodontis. IL-5, in contrast to IL-4, is crucial for the containment of adult worms during short- and long-term infections. IL-5 KO mice allowed development of more larvae into adult worms and showed up to 200 times more adult worms persisting during chronic infection (day 60 until 200 post-infection). This increased persistence was accompanied by a reduction in inflammatory nodules around adult filariae. In contrast, adult worm survival and nodule formation did not differ between BALB/c wild-type mice and BALB/c IL-4 KO or BALB/c IL-4 receptor (IL-4R) alpha-chain KO mice. In both IL-4 and IL-5 KO mice microfilaraemia was greatly enhanced (160-fold) and prolonged compared to wild-type mice. This extent of susceptibility to microfilariae required the presence of adult worms in a full infection cycle since upon intraperitoneal injection of microfilariae alone they were removed from BALB/c, BALB/c IL-4 KO and BALB/c IL-4R alpha-chain KO mice with equivalent kinetics, and since microfilarial survival was only slightly increased in IL-5 KO mice (factor of 5 vs. factor of 160 in full infection). In conclusion, IL-4 and IL-5 dependent effector pathways operate against different stages of filarial worms, and IL-5 has a greater impact on parasite containment than IL-4.

Animals↗
PubMed2002

Involvement of Toll-like receptor 4 in the embryogenesis of the rodent filaria Litomosoides sigmodontis.

To examine the role that lipopolysaccharide (LPS)-like molecules from the filarial intracellular endobacteria Wolbachia might play in the development of filarial infections, a natural infection in the LPS-nonresponsive C3H/HeJ mouse strain was compared to that of the LPS-responsive C3H/HeN mouse strain. C3H/HeN mice have been shown to be susceptible to the rodent filarial nematode Litomosoides sigmodontis, with the development of adult worms including females containing mature microfilariae (first stage larvae) in the uterine tubes. However, free microfilariae are not detected. In this study the worm burden and worm length were not significantly different between the C3H/HeN and C3H/HeJ mice. However, the fertility of worms from CeH/HeJ mice was found to be higher than those from C3H/HeN mice. Significantly, mature microfilariae were found at the site of infection only in C3H/HeJ mice. These results indicate a role for TLR4 signaling in the immune response that inhibits worm embryogenesis and prevents the release of microfilariae or directly kills released microfilariae.

Animals↗
PubMed2004

Increased early local immune responses and altered worm development in high-dose infections of mice susceptible to the filaria Litomosoides sigmodontis.

The relationship between the number of larvae inoculated and filarial infection outcome is an important fundamental and epidemiological issue. Our study was carried out with BALB/c mice infected with the filaria Litomosoides sigmodontis. For the first time, an immunological analysis of infection with various doses was studied in parallel with parasitological data. Mice were inoculated with 200, 60 or 25 infective larvae (third stage larvae, L3), and monitored over 80 days. At 60 h post-inoculation the immune response was stronger in the 200 L3 group than the 25 L3 group. Cells from lymph nodes draining the site of inoculation proliferated intensely and produced large amounts of IL-5 and IL-4. In the pleural cavity, leukocyte populations accumulated earlier and in larger quantities. IgG1, IL-4 and IL-10 serum concentrations were transiently higher. During the first 10 days the worm recovery rates were identical in all groups, but decreased thereafter in the 200 L3 group. In this group, the development of the worms was altered, with reduced lengths, diminished intra-uterine production of microfilariae and abnormalities of male copulatory organs. Whereas mice inoculated with 25 L3 became microfilaraemic, only one third reached patency in the 200 L3 group. However, detrimental effects of high numbers of worms are not seen in studies using different inoculation protocols. This suggests that the very early events determine subsequent immune response and infection outcome rather than competitive interactions between the worms.

Animals↗
PubMed2004

The antifilarial activity of a marine red alga, Botryocladia leptopoda, against experimental infections with animal and human filariae.

The antifilarial activity of the marine red alga Botryocladia leptopoda against rodent and human lymphatic filarial parasites is described. The animal filarial species included Litomosoides sigmodontis and Acanthocheilonema viteae maintained in cotton rats and Mastomys coucha, respectively, while a subperiodic strain of the human lymphatic filarial parasite Brugia malayi was maintained in M. coucha. The crude extract and its hexane fraction brought about a marked reduction in the peripheral microfilarial level in both of the rodent filarial parasites L. sigmodontis and A. viteae. The microfilaricidal effect began slowly from day 8 or 15 after initiation of treatment and increased with time with a very high efficacy at the end of the observation period against both rodent filariids. The microfilaricidal efficacy was, however, not as prominent in the case of B. malayi. The antifilarial activity, which occurred in the hexane fraction, exerted action at a much lower dose. The product killed a significant proportion of A. viteae and L. sigmodontis adult parasites. In the case of B. malayi, although the macrofilaricidal efficacy was much less than that of the rodent parasites, it (hexane fraction) caused sterilization of a significant proportion of the surviving female parasites. The present findings indicate the possibility of developing an adulticidal and female sterilizing agent against filarial parasites from a marine red alga.

Animals↗
PubMed2004

The bacterial catalase from filarial DNA preparations derives from common pseudomonad contaminants and not from Wolbachia endosymbionts.

Wolbachia are obligatory endosymbionts in many species of filarial nematodes. Certain bacterial molecules induce antibody responses in mammalian hosts infected with filariae, while others activate inflammatory responses that contribute to pathology. These findings, coupled with antibiotic studies demonstrating the dependence of filarial embryogenesis on the presence of Wolbachia, have intensified research on Wolbachia-nematode interactions, and the effects of Wolbachia molecules on the mammalian immune system. By amplification and sequencing of 16S rDNA and catalase sequences, we show that filarial DNA samples prepared from nematodes collected under typical conditions are frequently contaminated with Pseudomonas DNA. Analysis of a published DNA fragment containing a catalase attributed to the Wolbachia of Onchocerca volvulus showed it to be most like Pseudomonas, both in terms of sequence similarity and genomic organization. Additionally, there was no obvious catalase in either of two available Wolbachia genome sequences. Contamination of filarial DNA with bacterial sequences other than Wolbachia can complicate studies of the role of these symbionts in filarial biology.

Animals↗
PubMed2000

Immunomodulatory effects in Litomosoides sigmodontis-infected Mastomys coucha.

The levels of parasite-specific IgG1 and IgG2 antibodies and mitogen-induced and parasite-specific proliferative T-cell responses were determined in Litomosoides sigmodontis-infected Mastomys coucha throughout an observation period of 400 days post infection (p.i.). These were compared with the respective reactions in animals that had been immunized with intrauterine stages/microfilariae of the parasite and in animals that had been challenged after immunization as determined at up to 60 days after challenge. IgG1 antibodies to adult antigen developed early and reached a plateau at 120 days p.i., whereas IgG2 antibodies were not found before day 60 p.i., increased with rising parasitemia, reached a plateau at 200 days p.i., and, in some animals, even became the predominant IgG subclass. Proliferative responses of spleen lymphocytes to concanavalin A (Con A) and lipopolysaccharides (LPS), but not Con-A-induced interleukin 2 (IL-2) production, were found to be suppressed in infected animals during patency as compared with uninfected controls. Spleen cells of infected animals showed a weak proliferative reaction to male antigen but were unresponsive to female and microfilarial antigen during prepatency and early patency. Subsequently, when microfilaremia decreased (200 days p.i.), continuously increasing responses to all antigens were observed. Immunized M. coucha developed specific IgG1 and IgG2 antibodies, and their spleen cells showed strong proliferative responses to the three L. sigmodontis antigens. Challenge infections down-regulated the proliferative responses of spleen cells to filarial antigens as early as during the prepatent phase of the challenge infection but supported existing IgG1 and IgG2 responses.

Animals↗
PubMed2005

Description of adult and fourth-stage larva of Litomosoides navonae n. sp. (Nematoda: Onchocercidae), a parasite of five species of sigmodontine rodents from northeastern Argentina.

This study describes a new species of Litomosoides Chandler, 1931, parasitic in five different sigmodontine rodents from Misiones, Chaco and Formosa provinces of Argentina. The fourth-stage (L4) larva (male and female) is also described. L. navonae n. sp. exhibits: a bottle-shaped buccal cavity; a buccal capsule with irregularly crenate external walls; four externo-labial papillae and one ventral cephalic papilla; a well differentiated oesophagus; and sigmodontis-type spicules. The microfilaria is fusiform, with a large sheath. The L4 has a buccal capsule which is relatively longer than that of the adults, with narrower walls and a bottle-shaped lumen. It was observed in this species that the oesophagus/body-length ratio increases from larva to adult (female ratio 26.2-28.3 in larva; 88.4 in adults), and the vulva appears to move further posterior to the oesophago-intestinal junction (200-300 microm in larvae vs a mean of 600 microm in adults). L. navonae was found parasitising: Nectomys squamipes from the Reserve UNLP Valle del Arroyo Cuñá Pirú, Misiones; Oligoryzomys chacoensis, Holochilus chacarius and Akodon azarae bibianae from the marshes of Arroyo Bellaco, El Colorado, Formosa; and O. fornesi and H. chacarius from Selvas del Río de Oro (Chaco). Both N. squamipes and H. chacarius harbour other filarioids species, i.e. L. kohnae Bain, Petit & Diagne, 1989 and L. patersoni (Mazza, 1928), respectively, throughout their range, but these filarioids are readily differentiated from L. navonae. These well-differentiated filarial species found in Nectomys and Holochilus could indicate how isolated the populations of rodents are and could be interpreted either as: (a) an early point in the speciation processes that could be taking place in these hosts; or (b) extra support for the capture phenomenon theory of the evolution of Litomosoides. New regions, such as southern Brazil and northern Argentina, need to be studied in order to clarify these alternatives.

Animals↗