Characterization of siderophores produced by different species of the dermatophytic fungiMicrosporum andTrichophyton

The dermatophytic fungiTrichophyton spp andMicrosporum spp secrete ferrichrome type siderophores under low iron conditions. Three different species ofMicrosporum, i.e.M. qypseum, M. canis andM. audouinii, as well asT. rubrum produce ferrichrome C and ferricrocin, whereasT. mentagrophytes andT. tonsurans produce only ferrichrome. The identification of the siderophores was established by means of thin layer chromatography, high performance liquid chromatography and mass spectroscopy.     

Prey-related odor preference of the predatory mites Typhlodromalus manihoti and Typhlodromalus aripo (Acari: Phytoseiidae)

Typhlodromalus manihoti and Typhlodromalus aripo are exotic predators of the cassava green mite Mononychellus tanajoa in Africa. In an earlier paper, we showed that the two predators were attracted to odors from M. tanajoa-infested cassava leaves. In addition to the key prey species, M. tanajoa, two alternative prey mite species, Oligonychus ossypii and Tetranychus urticae also occur in the cassava agroecosystem. Here, we used a Y-tube olfactometer to determine the attraction of the predators to odors from O. gossypii- or T. urticae-infested cassava leaves and their prey-related odor preference. T. aripo but not T. manihoti was slightly attracted to odors from O. gossypii-infested leaves. Both predator species showed a stronger response to odors from cassava leaves infested by M. tanajoa over odors from cassava leaves infested by O. gossypii. Neither predator species was attracted to odors from T. urticae-infested leaves and the predators preferred the odors from M. tanajoa-infested leaves over those from T. urticae-infested leaves. When O. gossypii was present together with M. tanajoa on the same leaves or on different sets of leaves offered together as an odor source the two predators were attracted. In contrast, after mixing non-attractive odors from T. urticae-infested leaves with attractive odors from M. tanajoa-infested leaves, neither T. aripo nor T. manihoti was attracted. Ecological advantages and disadvantages of the predators’ behavior and possible implications for biological control of M. tanajoa are discussed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Eastern Cottontail (<Emphasis Type="Italic">Sylvilagus Floridanus)</Emphasis> as Carrier of Dermatophyte Fungi

Eastern cottontail (Sylvilagus floridanus, fam. Leporidae), introduced into Piedmont (Italy) in the 1960s, was studied as carrier of dermatophyte fungi. Of 216 hair samples collected from animals culled between September 1999 and July 2000 in the Province of Alessandria (Piedmont, Italy) during a pest control project, 57 (26.4%) yielded dermatophyte colonies. As two different species of dermatophytes grew from two samples, a total of 59 fungal isolates (26.5%) were obtained. Six dermatophyte species both geophilic (M. gypseum, M. cookei, Trichophyton ajelloi, T. terrestre) and zoophilic (M. canis, T. mentagrophytes) were identified. No sex-related differences were found but season-related differences were observed. The highest prevalence of dermatophyte-positive samples was recorded in May–September, due to the geophilic fungi whose prevalence decreased during colder and increased during warmer months ( p < 0.001). The presence of zoophilic dermatophytes, T. mentagrophytes, commonly associated with rodents, small mammals and lagomorphs and M. canis, usually correlated with domestic environment, did not change the whole year round. As Eastern cottontail has been showed to be a carrier of dermatophytes transmissible to man (M. canis, T. mentagrophytes and M. gypseum), it may represent a source of infection for gamekeepers, hunters and veterinarians.     

Attraction of the predatory mites Typhlodromalus manihoti and Typhlodromalus aripo to cassava plants infested by cassava green mite

The attraction of the predatory mites, Typhlodromalus manihoti and Typhlodromalus aripo, to the host plant-spider mite complex, Manihot esculenta – Mononychellus tanajoa, was investigated with a Y-tube olfactometer. Factors examined included predator starvation period, several combinations of cassava leaf biomass and initial M. tanajoa infestations, M. tanajoa-damaged leaves with mites and/or their residues removed, M. tanajoa alone, and mechanically damaged cassava leaves. We found that females of T. manihoti and T. aripo were significantly attracted to M. tanajoa-infested cassava leaves when the predators were starved for 2, 6, or 10 h. Satiated T. aripo was significantly attracted to infested cassava leaves whereas satiated T. manihoti did not discriminate between infested and non-infested leaves. When a choice was given between either two or four leaves infested with 200 female M. tanajoa and an equivalent number of non-infested leaves, 2 h-starved T. manihoti and T. aripo were significantly attracted to each of the infested groups of cassava leaves. At a density of 12 female M. tanajoa per leaf on four leaves, 2 h-starved T. manihoti was still attracted to M. tanajoa-infested leaves whereas 2 h-starved T. aripo was not attracted. When a choice was given between non-infested cassava leaves and either infested leaves from which only M. tanajoa females had been removed, or infested leaves from which all M. tanajoa and their visible products (web, feces) had been wiped off, T. aripo preferred odors from both types of previously infested leaves. Typhlodromalus manihoti was only attracted to infested leaves from which the M. tanajoa females only had been removed. Finally, the two predators were not attracted to 400 female M. tanajoa on clean cotton wool or to mechanically wounded leaves. This supports the hypothesis that M. tanajoa damage induces volatile cues in cassava leaves that attract T. manihoti and T. aripo to M. tanajoa-infested leaves.     

ThenadB gene ofSalmonella typhimurium complements the nicotinic acid auxotrophy ofShigella flexneri

Shigella species are characteristically nicotinic acid (NA) auxotrophs. The invasiveS. flexneri strain M90T, transformed with the multicopy plasmid pZT349 encoding thenadB gene ofSalmonella typhimurium, can grow in minimal glucose medium without exogenous NA, whereas, M90T containing the control vector, pUC18 does not, suggesting that this species lacksl-aspartic acid oxidase, the first enzyme in the de novo NAD biosynthetic pathway. The estimated growth rate of strain M90T (pZT349) in HeLa cells was identical to that of M90T (pUC18), indicating the available intracellular concentration of NA is not limiting for bacterial growth.     

Effect of brassicaceous plants on the survival and infectivity of insect pathogenic fungi

Studies were conducted to investigate potentialinteractions between brassicaceous plants, theisothiocyanates they produce and insectpathogenic fungi. Studies in vitro showedthat 100 ppm of 2-phenylethyl isothiocyanatecompletely inhibited growth of Metarhiziumanisopliae and Tolypocladiumcylindrosporum. T. cylindrosporum wassignificantly inhibited by 10 ppm 2-phenylethylisothiocyanate, but not by 1 ppm. M.anisopliae was not inhibited by 10 or 1 ppm2-phenylethyl isothiocyanate. The effect offreshly grated rutabaga on virulence of M.anisopliae to Galleria mellonella larvaewas also tested, resulting in reduced infectionby M. anisopliae. To study the effect ofplants in the Brassicaceae under morefield-like conditions fungi were added to soilwithout plants or at the bases of two differentplant species, Barbarea vulgaris and Eruca vesicaria sativa. Soil was sampled at 5,10 and 15 days to determine the concentrationof colony forming units (CFUs). Treatments withplants did not have fewer CFUs than thecontrol. Instead significantly fewer CFUsresulted when M. anisopliae was added topots with soil only than to pots with plants.There were no significant differences betweenthe two plant species in the number of CFUs atday 5. For days 10 and 15, however,significantly more M. anisopliae CFUswere found in pots containing E. vesicariasativa than B. vulgaris. T.cylindrosporum was less affected by thedifferent treatments than M. anisopliae.Our studies demonstrated that whileisothiocyanates can inhibit insect pathogenicfungi in Petri dishes, when using a morerealistic fungus/plant/soil microcosm no fungalinhibition was found.     

Effect of antimicrobial activity of Melaleuca alternifolia essential oil on antagonistic potential of Pleurotus species against Trichoderma harzianum in dual culture

Melaleuca alternifolia (tea tree) essential oil was investigated for its “in vitro” ability to control Trichoderma harzianum, a fungal contaminant that causes extensive losses in the cultivation of Pleurotus species. The antifungal activity of M. alternifolia essential oil and antagonist activities between Pleurotus species against three T. harzianum strains were studied in dual-culture experiments on an agar-based medium in which different concentrations of essential oil were incorporated. M. alternifolia essential oil at a concentration of 0.625 μL/mL, inhibited T. harzianum mycelial growth by 5.9–9.0%, depending on the strain. At the same concentrations P. ferulae and P. nebrodensis stimulated mycelial growth by 5.2–8.1%. All strains of T. harzianum were antagonistic to the Pleurotus species in the control. When essential oil was added to the substrate cultural, the antagonistic activity of T. harzianum against the Pleurotus species was weak (0.0625 μL of essential oil) or non-existent (0.125 μL of essential oil). M. alternifolia essential oil could be an alternative to the synthetic chemicals that are currently used to prevent and control T. harzianum in mushroom cultivation.     

Comparative bioactivity of selected extracts from Meliaceae and some commercial botanical insecticides against two noctuid caterpillars, <Emphasis Type="Italic">Trichoplusia ni</Emphasis> and <Emphasis Type="Italic">Pseudaletia unipuncta</Emphasis>

Plant-derived extracts and phytochemicals have long been a subject of research in an effort to develop alternatives to conventional insecticides but with reduced health and environmental impacts. In this review we compare the bioactivities of some plant extracts with those of commercially available botanical insecticides against two important agricultural pests, the cabbage looper, Trichoplusia ni and the armyworm, Pseudaletia unipuncta. Test materials included extracts of Azadirachta indica (neem), A. excelsa (sentang), Melia volkensii, M. azedarach (Chinaberry) and Trichilia americana, (all belonging to the family Meliaceae) along with commercial botanical insecticides ryania, pyrethrum, rotenone and essential oils of rosemary and clove leaf. Most of the extracts and botanicals tested proved to be strong growth inhibitors, contact toxins and significant feeding deterrents to both lepidopteran species. However, there were interspecific differences with T. ni generally more susceptible to the botanicals than the armyworm, P. unipuncta. All botanicals were more inhibitory to growth and toxic (through feeding) to T. ni than to P. unipuncta, except for M. azedarach which was more toxic to P. unipuncta than to T. ni. Athough, pyrethrum was the most toxic botanical to both noctuids, A. indica, A. excelsa, and M. volkensii were more toxic than ryania, rotenone, clove oil and rosemary oil for T. ni. As feeding deterrents, pyrethrum was the most potent against T. ni, whereas A. indica was the most potent against the armyworm. Based upon growth inhibition, chronic toxicity, and antifeedant activity, some of these plant extracts have levels of activity that compare favorably to botanical products currently in commercial use and have potential for development as commercial insecticides.     

The role of host semiochemicals in parasitoid specificity: a case study with Trissolcus brochymenae and Trissolcus simoni on pentatomid bugs

The role of semiochemicals on host specificity of two egg parasitoid species, the European Trissolcus simoni and the American Trissolcus brochymenae (Hymenoptera: Scelionidae), was studied in an olfactometer and in different arenas. Cues from two allopatric pests of cabbage, the European Eurydema ventrale and the American Murgantia histrionica (Heteroptera: Pentatomidae), and from the polyphagous and cosmopolitan Nezara viridula were tested. Both T. simoni and T. brochymenae responded to volatile and contact cues from their co-evolved hosts E. ventrale and M. histrionica, respectively, thus confirming the role of host semiochemicals in host location and recognition. When cues of non-co-evolved hosts were presented, a partial “new association” was obtained, as T. simoni probed and oviposited in M. histrionica eggs and some adult emergence occurred. However, this association is unlikely to occur in the field because T. simoni did not respond to volatile cues of M. histrionica. Instead T. brochymenae partially responded to volatile and contact cues from E. ventrale, but eggs were rarely accepted and parasitoids did not develop in this host. When N. viridula was tested, T. simoni responded only to contact cues, whereas T. brochymenae partially responded to volatile and contact cues, but N. viridula eggs were not suitable for development. Therefore, the N. viridula–T. brochymenae association reported from the literature appears unreliable. Understanding the mechanisms that result in host specificity may help increase parasitoid safety and predict their efficacy in biological control with old or new associations.     

Inhibition of Telenomus sphingis an egg parasitoid of Manduca spp. by trichome/2-tridecanone-based host plant resistance in tomato

The resistance of accession PI 134417 of the wild tomato Lycopersicon hirsutum f. glabratum C. H. Mull to Manduca sexta (L.) (Lepidoptera: Spingidae) and Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae) is conditioned by the high densities of 2-tridecanone-containing, glandular trichomes associated with the foliage. In laboratory experiments, rates of parasitism of M. sexta eggs by Telenomus sphingis (Ashmead) (Hymenoptera: Scelionidae) were lower among eggs on PI 134417 foliage than among eggs on foliage of the cultivated tomato L. esculentum Mill. (cv. Better Boy). The latter is characterized by a significantly lower density of type VI glandular trichomes than PI 134417 and an absence of 2-tridecanone. Parasitism by T. sphingis was also reduced among eggs on foliage of the F₁ hybrid between PI 134417 and L. esculentum. The hybrid foliage lacks 2-tridecanone but has a density of type VI glandular trichomes that is intermediate between those of PI 134417 and L. esculentum, indicating that elevated densities of type VI glandular trichomes adversely affect T. sphingis. This conclusion was further substantiated by the finding that there were no differences among plant lines in the levels of parasitism of M. sexta eggs when the eggs were on foliage that had been divested of glandular trichomes.In bioassays in which T. sphingis adults or immatures in host eggs were exposed to filter paper treated with 2-tridecanone at rates comparable to those associated with PI 134417 foliage, 2-tridecanone was acutely toxic and caused high levels of mortality. In addition, at high concentrations, 2-tridecanone vapors were repellent to T. sphingis adults. However, when exposed to PI 134417 foliage, few T. sphingis adults were killed.Parasitism of M. sexta eggs was unaffected when the eggs were deposited by moths reared as fifth instar larvae on diet containing 2-tridecanone and/or 2-undecanone at levels comparable to those associated with PI 134417 foliage.     

Optimization of formation and regeneration of protoplasts from biocontrol agents ofTrichoderma species

The optimal conditions necessary for a large yield and a high frequency of regeneration of protoplasts isolated from the biocontrol agentsTrichoderma koningii andT. harzianum were investigated. Protoplast yields were 1.2×10⁸/ml fromT. koningii and 6×10⁷/ml fromT. harzianum when 20-h mycelial culture was treated with a lytic enzyme solution containing Novozym 234 (15 mg/ml), sucrose (0.6 M) and citrate phosphate buffer (0.02 M), pH 5.6 at 31°C. When the protoplasts were grown in the regeneration medium containing yeast extract (1.5%), 1 I of Mandel's salts, pH 5.6, and glucose (0.8 M), a high frequency of regeneration of the protoplast was obseved: 66% forT. koningii and 45% forT. harzianum. Two patterns of regeneration were observed. First, the hyphae arose directly from the regenerated protoplast mother cell. Second, a chain of bud cells developed from the protoplast and subsequently generating hyphae generally protruded from the terminal bud cells.     

Books received

Chromolaena ternicapitulata is described from Sierra de Maigualida in T. F. Amazonas and a key to the species of Chromolaena from Guayana is given. Newly documented for the flora of Venezuela are M. aschersonii Hieron. and M. amazonica Baker, the second herein resurrected from the synonymy of common and widespread M. sprucei Baker. Mikania karsteniana Klot. ex Hieron. is not considered synonymous with M. pannosa Baker, thus the latter is again considered to be endemic to Guayana.     

Keratinolysis and its morphological expression in hair digestion by airborne fungi

The morphological expression of keratinolysis in fungi isolated from the air of Torino (98 isolates belonging to 36 species) was studied. Light microscopy on whole material and on semithin sections, as well as scanning electron microscopy was used. There were 19 keratinolytically active species, with seven in the genusChrysosporium (C. indicum, C. keratinophilum, C. pannicola, C. tropicum, C. an.Arthroderma cuniculi, C. an.Pectinotrichum llanense, C. an.Renispora flavissima), four in the genusMalbranchea (M. arcuata, M. fulva, M. sulphurea, M. st.Uncinocarpus reesii), and three in the genusTrichophyton (T. mentagrophytes, T. rubrum, T. terrestre). In addition there wereAphanoascus fulvescens, Beauveria bassiana, Geomyces pannorum v.pannorum, Gymnoascus umbrinus andMyceliophthora vellerea. Most of these species were capable of developing structures related to surface erosion and radial penetration contemporaneously. HoweverGymnoascus umbrinus, Myceliophthora vellerea, an isolate ofC. indicum, C. tropicum andTrichophyton mentagrophytes demonstrated only surface erosion. Different isolates of one species can vary in their production of invasive structures and in degree of keratinolytic activity. Thus such activity, like many biochemical activities of fungi, does not appear to be a constant or rigorously species-specific character.     

<Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Melastoma malabathricum</Emphasis> and <Emphasis Type="Italic">Tibouchina semidecandra</Emphasis> with sense and antisense dihydroflavonol-4-reductase (DFR) genes

Genetic engineering of a wide variety of plant species has led to the improvement of plant traits. In this study, the genetic transformation of two potentially important flowering ornamentals, Melastoma malabathricum and Tibouchina semidecandra, with sense and antisense dihydroflavonol-4-reductase (DFR) genes using the Agrobacterium-mediated method was carried out. Plasmids pBETD10 and pBETD11, each harbouring the DFR gene at different orientations (sense and antisense) and selectable marker nptII for kanamycin resistance, were used to transform M. malabathricum and T. semidecandra under the optimized transformation protocol. Putative transformants were selected in the presence of kanamycin with their respective optimized concentration. The results indicated that approximately 4.0% of shoots and 6.7% of nodes for M. malabathricum regenerated after transforming with pBETD10, whereas only 3.7% (shoots) and 5.3% (nodes) regenerated with pBETD11 transformation. For the selection of T. semidecandra, 5.3% of shoots and 9.3% of nodes regenerated with pBETD10 transformation, while only 4.7% (shoots) and 8.3% (nodes) regenerated after being transformed with pBETD11. The presence and integration of the sense and antisense DFR genes into the genome of M. malabathricum and T. semidecandra were verified by polymerase chain reaction (PCR) and nucleotide sequence alignment and confirmed by southern analysis. The regenerated putative transformants were acclimatized to glasshouse conditions. Approximately 31.0% pBETD10-transformed and 23.1% pBETD11-transformed M. malabathricum survived in the glasshouse, whereas 69.4% pBETD10-transformed and 57.4% pBETD11-transformed T. semidecandra survived. The colour changes caused by transformation were observed at the budding stage of putative T. semidecandra transformants where greenish buds were produced by both T. semidecandra harbouring the sense and antisense DFR transgenes. Besides that, the production of four-petal flowers also indicated another morphological difference of putative T. semidecandra transformants from the wild type plants which produce five-petal flowers.     

Entry and intracellular location of Mycoplasma hominis in Trichomonas vaginalis

The parasite Trichomonas vaginalis causes one of the most common non-viral sexually transmitted infections in humans. The coexistence of different sexually transmitted diseases in the same individual is very common, such as vaginal infections by T. vaginalis in association with Mycoplasma fermentans or Mycoplasma hominis. However, the consequences and behavior of mycoplasma during trichomonad infections are virtually unknown. This study was undertaken to elucidate whether mycoplasmas enter and leave trichomonad cells and if so how. M. hominis was analyzed in different trichomonad isolates and the process of internalization and the pathway within the parasite was studied. Parasites naturally and experimentally infected with mycoplasmas were used and transmission electron microscopy, cytochemistry and PCR analyses were performed. The results show that: (1) M. hominis enters T. vaginalis cells by endocytosis; (2) some mycoplasmas use a terminal polar tip as anchor to the trichomonad plasma membrane; (3) some trichomonad isolates are able to digest mycoplasmas, mainly when the trichomonads are experimentally infected; (4) some fresh virulent isolates are able to maintain mycoplasmas as cohabitants in the cell’s interior; (5) some mycoplasmas are able to escape from the vacuole to the trichomonad cytosol, and trichomonad plasma membrane budding suggested that mycoplasmas could leave the parasite cell.     

Decreased Response to Feeding Deterrents Following Prolonged Exposure in the Larvae of a Generalist Herbivore, Trichoplusia ni (Lepidoptera: Noctuidae)

We investigated the role of experience with several antifeedants on the feeding behavior of a generalist herbivore, Trichoplusia ni. Second-, third-, and fifth-instar larvae of T. ni were examined for their feeding responses to plant extracts (Melia volkensii, Origanum vulgare) and individual plant allelochemicals (cymarin, digitoxin, xanthotoxin, toosendanin, and thymol), after being exposed to them continually beginning as neonates. All tested instars of T. ni were capable of showing a decreased antifeedant response following prolonged exposure to most of the antifeedants tested compared with their naive conspecifics. Cardenolides (digitoxin and cymarin) were the exceptions. The response to oregano was affected as a result of previous exposure to different concentrations of oregano, unlike M. volkensii, leading us to conclude that T. ni sensitivity varies between stimuli and cannot be generalized. To demonstrate that decreased deterrence following prolonged exposure to M. volkensii was the result of learned habituation, three aversive stimuli were used. A high concentration of the particular antifeedant, xanthotoxin, acted as a noxious stimulus and dishabituated (reversed) the decrement in the antifeedant response to M. volkensii. Cold shock or CO₂ was marginally effective in dishabituating the response. The fact that the decrease in antifeedant response can be dishabituated has implications for pest management.     

Endocrinological investigation into the reproductive cycles of two sympatric skate species, Malacoraja senta and Amblyraja radiata, in the western Gulf of Maine

The smooth skate, Malacoraja senta, and thorny skate, Amblyraja radiata, are two commercially exploited batoids found within the Gulf of Maine. During the past five years, we conducted a large study to accurately describe important biological life history parameters previously lacking for these species. As part of that project, the current study reports our findings on the hormonal profiles associated with the reproductive cycles of M. senta and A. radiata. Blood samples were obtained from mature M. senta and A. radiata of both sexes from all months of the year, and plasma testosterone (T), estradiol (E₂) and progesterone (P₄) concentrations were determined using radioimmunoassay (RIA). In female M. senta and A. radiata, monthly T concentrations ranged from 4,522 pg ml⁻¹ to 1,373 pg ml⁻¹ and 31,940 pg ml⁻¹ to 14,428 pg ml⁻¹, E₂ concentrations from 831 pg ml⁻¹ to 60 pg ml⁻¹ and 8,515 pg ml⁻¹ to 2,902 pg ml⁻¹, and P₄ concentrations from 3,027 pg ml⁻¹ to 20 pg ml⁻¹ and 3,264 pg ml⁻¹ to 331 pg ml⁻¹, respectively. No statistical differences were detected between any months for any hormone. Estradiol concentrations were not correlated with ovary weight, shell gland weight, or diameter of the largest follicles in either species. Monthly T concentrations in male M. senta and A. radiata ranged from 23,146 to 12,660 pg ml⁻¹ and from 57,500pg ml⁻¹ to 24,737 pg ml⁻¹, while E₂ concentrations ranged from 7.5 pg ml⁻¹ to undetectable and 103 to 30 pg ml⁻¹, respectively. No statistical differences were observed between months for either steroid. Testosterone concentrations were weakly correlated with testes weight and percent of stage VI spermatocysts in A. radiata, however, no correlation was detected between T and stage VI spermatocysts in M. senta. Collectively, these data support the previous conclusion that M. senta and A. radiata of both sexes are capable of reproducing year round in the western Gulf of Maine.     

Etude sur la contamination par les champignons dermatophytes d'une population de petits mammiferes sauvages en Alsace

Résumé Des 3782 petits mammifères sauvages capturés au cours d'une enquête poursuivie pendant plus de 4 ans, 15,78% sont contaminés par des dermatophytes.Les espèces de dermatophytes ou champignons, apparentés qui sont rencontrées ne sont que 6;Microsporum persicolor etTrichophyton mentagrophytes sont les espèces dominantes. Les campagnols roussâtres sont, de façon significative, plus contaminés parM. persicolor (11,63%) que parT. mentagrophytes (4,36%). Au contraire, les mulots sont plus contaminés parT. mentagrophytes: 13,95% contre 3,50% contaminés parM. persicolor. Les campagnols roussâtres mâles (13,33%) sont plus contaminés que les femelles (9,45%) parM. persicolor et les mulots mâles (17,09%) plus contaminés que les femelles (9,95%) parT. mentagrophytes. La présence deM. persicolor est notée pour la première fois chez le grand hamster. L'étude histologique de certains animaux permet de remarquer l'existence de lésions dermatophytiques. A l'isolement deT. mentagrophytes correspond une attaque pilaire de type endo-ectothrix; à l'isolement deM. persicolor correspond une attaque limitée à l'épiderme.

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3782 small wild mammals trapped during a 4 year survey have been examined in relation to a possible contamination by dermatophytes. 15.78% of the animals were contaminated.The prevailing species wereMicrosporum persicolor andTrichophyton mentagrophytes. The bank voles were significantly more contaminated byM. persicolor (11.63%) than byT. mentagrophytes (4.36%). On the contrary the wood mice were more contaminated byT. mentagrophytes: 13.95% as against 3.50% contaminated byM. persicolor. The male bank voles (13.33%) were more contaminated than the females (9.45%) byM. persicolor and the male wood mice (17.09%) more contaminated than the females (9.95%) byT. mentagrophytes. The occurrence ofM. persicolor in common hamster is noted for the first time. The existence of a pathological lesion in relation to the fungal contamination was noted in the small group of rodents examined histologically: WhenT. mentagrophytes was isolated the hairs were invaded in the endo-ectothrix type pattern; whenM. persicolor was cultivated, hairs are not attacked but only the epidermis.

     

Use of indigenous fishes to control schistosome snail vectors in Mala i, Africa

The expansion of water resource development projects in the tropics and subtropics resulted in an increased transmission of human schistosomes. This study was conducted to test the feasibility of using two snail-eating fishes, Trematocranus placodon (Trewavas) and Maravichromis anaphyrmis (Trewavas), as biocontrol agents of schistosomes in fish ponds. The results suggest that T. placodon has a potential for controlling the snail vectors of Schistosoma mansoni (Sambon) and Schistosoma haematobium (Bilharz). The use of M. anaphyrmis, however, to control schistosome-carrying snails was not satisfactory.