Sand flea (Tunga spp.) infections in humans and domestic animals: state of the art.

Tungiasis is a parasitic disease of humans and animals caused by fleas (Siphonaptera) belonging to the genus Tunga. Two species, Tunga penetrans (L.) and Tunga trimamillata, out of 10 described to date, are known to affect man or domestic animals; the other eight are exclusive to a few species of wild mammals. Tunga penetrans and T. trimamillata originated from Latin America, although the first species is also found in sub-Saharan Africa (between 20 degrees N and 25 degrees S). Hundreds of millions of people are at risk of infection in more than 70 nations, mostly in developing countries. The second species has been reported only in Ecuador and Peru. Males and non-fertilized females of Tunga are haematophagous ectoparasites; pregnant females penetrate the skin where, following dilatation of the abdomen, they increase enormously in size (neosomy) and cause inflammatory and ulcerative processes of varying severity. The importance of Tunga infection in humans concerns its frequent localization in the foot, which sometimes causes very serious difficulty in walking, thereby reducing the subject's ability to work and necessitating medical and surgical intervention. Tungiasis in domestic animals can be responsible for economic losses resulting from flea-induced lesions and secondary infections. Because tungiasis represents a serious problem for tropical public health and because of the recent description of a new species (Tunga trimamillata), it seems appropriate to review current knowledge of the morphology, molecular taxonomy, epidemiology, pathology, treatment and control of sand fleas of the genus Tunga.

Three new cases of human infection with Dirofilaria repens, one pulmonary and two subcutaneous, in the Egyptian governorate of Assiut.

Human dirofilariasis caused by Dirofilaria repens is a parasitic infection, currently considered to be an emerging zoonosis, that has been observed in many areas of the Old World. Dogs are the main 'reservoir' host. In humans, D. repens can cause inflammatory nodules, most commonly in the subcutaneous tissues or in the subconjunctival space. Lung involvement, which is the most common of the non-cutaneous and non-ocular manifestations, is frequently mis-diagnosed as a primary or metastatic lung tumour. Two new subcutaneous cases and one new pulmonary case, all observed in the Egyptian governorate of Assiut, are described here. This represents the first report of human pulmonary dirofilariasis caused by D. repens on the African continent. All the worms collected from the cases, including a living worm from the left lung of the pulmonary case, were identified morphologically, and the identity of the lung parasite was confirmed by PCR.

Anatomy of Tunga trimamillata Pampiglione et al., 2002 (Insecta, Siphonaptera, Tungidae) and developmental phases of the gravid female.

This paper deals with some internal anatomical features observed in histological sections and freshly dissected mounts of Tunga trimamillata, a Siphonaptera recently discovered in Andean regions of Ecuador from several mammals, including man. It was possible to study in males and also non-gravid and gravid females, the location and anatomy of several organs not previously described for this species: the testes, epididymis, ganglia, Malpighian tubules, eyes, rectal ampulla with one of its pads and structures which could be interpreted as midgut diverticula, whose presence has not been recorded in the Siphonaptera. The process of neosomy in the female during pregnancy is illustrated by photographs of the consecutive developmental phases, taken at the stereomicroscope. Furthermore, some details of the exoskeleton, spermatheca during different phases of pregnancy of the gravid female and the presence of a foreign body (parasite?) within the haemocoel have been displayed in specimens cleared with Hoyer's medium.

Molecular characterization of Tunga trimamillata and T. penetrans (Insecta, Siphonaptera, Tungidae): taxonomy and genetic variability.

A new species of the genus Tungo, T. trimamillata has recently been described on the basis of several morphological traits. To explore the taxonomic status of this flea with respect to T. penetrans, we undertook a molecular analysis of cytochrome oxydase II and 16S rDNA mitochondrial genes and of the internal transcribed spacer 2 nuclear marker on samples of both species. Maximum Parsimony evaluations of the three data set indicate a differentiation compatible with a specific rank between the two fleas with very high levels of divergence. Both mitochondrial and nuclear data are in line with a recent bottleneck in the Malagasy population of T. penetrans, possibly due to the recent colonisation of Africa via human transportation. Further, significantly lower mitochondrial variability in the Ecuadorian populations of T. penetrans with respect to the T. trimamillata ones is also evidenced.

Acaricidal activity of aqueous extracts of camomile flowers, Matricaria chamomilla, against the mite Psoroptes cuniculi.

Arcaricidal properties of decoctions, infusions and macerates of dried flower heads of camomile, Matricaria chamomilla L. (Asterales: Asteraceae) were tested in vitro against the mite Psoroptes cuniculi Delafond (Parasitiformes: Psoroptidae). This mite species is responsible for otoacariasis in domestic animals. Mites were exposed to the extracts for 24, 48 or 72 h. All the extracts tested showed highly significant acaricidal activity when compared with controls. Among them, a decoction of 10% was the only formulation which gave 100% activity at all the three observations times.

Differential diagnosis between Tunga penetrans (L., 1758) and T. trimamillata Pampiglione et al., 2002 (Insecta, Siphonaptera), the two species of the genus Tunga parasitic in man.

Of the ten currently known species of sand fleas, only two, Tunga penetrans and Tunga trimamillata, are known to be parasites of man, besides other warm blooded animals, most of which are peridomestic. The hosts of the other eight are limited to a few genera of wild mammals. T. trimamillata was only recently identified and differentiated from T. penetrans by features of the gravid female phase. In the present paper the different morphological characters of both for non-gravid females and males of the two species are described. In the non-gravid-females the distinguishing characters are: a) differences in the length of the first two segments of the maxillary palps (the first is the longest in T. trimamillata, whereas the second is the longest in T. penetrans), this feature is associated with another character i.e. the presence of short, thick spines in addition to the bristles on the surface of the segments only in T. trimamillata; b) the presence, only in T. trimamillata, of a row of spines on the antero-medial surface of the libia of the 3rd pair of legs; c) the last abdominal spiracle protrudes in T. trimamillata but not in T. penetrans; d) the hood of the hilla in spermatheca is surrounded by a papilla only in T. penetrans. The following morphological characters differentiate males of T. trimamillata and T. penetrans: a) T. trimamillata has a row of spines on the antero-medial surface of the tibia of the 3rd pair of legs; b) the diameter of the abdominal spiracles of T. trimamillata is smaller than that of T. penetrans and the edges of the spiracles are more regular; c) the claspers and aedeagus of T. trimamillata are shorter than those of T. penetrans; d) the profile of the oedeagal apodeme differs between the two species.

Diagnosis of orf virus infection in humans by the polymerase chain reaction.

The orf virus is the causal agent of contagious ecthyma in goats and sheep. The infection can be transmitted to humans and represents a typical example of occupational zoonosis. In Italy, the incidence of human infection remains uncertain because the disease is rarely reported or diagnosed. In this paper, we report a case of human orf virus infection and the laboratory methods of diagnosis. We demonstrated a genomic identity between the conserved and the variable regions of the genome of the viral strains isolated from the human patient and from the infected sheep confirming that there is no specific clone infecting humans rather than animals.

[Two new human cases of dirofilariasis in Sardinia]. / Dirofilariasi in Sardegna: due nuovi casi nell'uomo.

Two new human cases of dirofilariasis, both due to Dirofilaria (Nochtiella) repens, recently occurring in Nuoro province (Sardinia) on people permanently resident in the island, are described. The parasite was located in one case into the uterine round ligament, in the other it was subconjunctival. Some observations about the diagnostic difficulties in the first one and the dramatic symptoms in the second, whose parasite was yet alive during the surgical ablaction, are discussed. These cases are the 9th and the 10th, respectively, reported in man in Sardinia, but it is possible that other cases are undiagnosed and consequently are not published.

Additional description of a new species of Tunga (Siphonaptera) from Ecuador.

A new species of chigoe flea belonging to the genus Tunga Jarocki, 1838 (Siphonaptera, Pulicidae, Tunginae), Tunga trimamillata, was recently described by Pampiglione et al. (2002). A better description and more details of the epidemiology of the flea are now presented. It is a species found in goats, pigs and cattle in Santa Isabel in Andean Ecuador. This new species differs from its most similar congener, Tunga penetrans (L., 1758), by several features, the most important of which are a) the presence on the anterior extremity of the gravid female of three rounded humps surrounding the head and thorax (which, however, are not visible if viewed in profile), b) slightly larger dimensions and c) the length of the first segment of the maxillary palpi which is longer than each of the other three.

[On a new species of sand flea from Ecuador and tungiasis, a problem of Public Health in many developing countries]. / Su di una nuova specie di pulce penetrante dell'Ecuador esulla tungiasi, problema di Sanità Pubblica in molti paesi in via di sviluppo.

The authors recently described a new species of sand flea (genus Tunga) occurred in goat, sheep, cow, pig and man, in the Andean village of S.ta Isabel (Ecuador) and named Tunga trimamillata. Its most important morphological characteristics are: slightly larger dimensions than T. penetrans, both in male and female; presence on the anterior extremity of gravid female of three rounded humps surrounding head and thorax; length of the first segment of maxillary palpi which is longer than each of the other three. The importance of this parasite is due to the fact that it can cause the same damages as T. penetrans both in humans and domestic animals, with conseguent walking difficulties and local or generalized infections. For breeders, economic losses can be remarkable. Tungiasis is a serious problem of Public Health in many countries of Latin America and Subsaharian Africa, and it can be considered in these localities as an indicator of underdevelopment and poor hygiene conditions.

Human dirofilariasis in Italy: a new case in the spermatic cord.

A new case of human dirofilariasis associated with Dirofilaria (Nochtiella) repens (Nematoda, Filarioidea, Onchocercidae) located in the spermatic cord is reported in a 71-year-old man from the province of Campobasso (Central Italy). When clinical signs pointed to a testicular tumor, a monolateral orchifuniculectomy was performed. According to the scientific literature, this case appears to be exceptional in its location, being only the eighth such case recorded in the world until now. The nematode, as well as the presence of vectors suitable for its transmission, had already been observed both in dogs and in humans (3 subcutaneous cases) in the same geographical area.

Dirofilariasis due to Dirofilaria repens in Italy, an emergent zoonosis: report of 60 new cases.

AIMS: Sixty new cases of human dirofilariasis due to Dirofilaria repens, occurring in Italy between 1990 and 1999, are presented. This is the most extensive case study of this zoonosis reported worldwide by a single study group. The aim is to utilize this large experience to characterize the different histopathological findings in the parasitic lesions in man. METHODS AND RESULTS: Diagnosis was performed on histological sections of the nematode enclosed in the nodules excised at biopsy or surgery. The nematode was located in the subcutaneous tissue (49 cases), the epididymis (two cases), the spermatic cord (two cases), the lung (two cases), the breast (two cases), the omentum (two cases) and under the conjunctival tissue (one case). The majority of cases (46) were from Piedmont; the remainder were from Emilia-Romagna, Sardinia, Sicily, Tuscany, Apulia and Lombardy. The histopathological features of the lesions are described and the clinical and epidemiological aspects of the zoonosis are discussed. The prevalence in Italy in general and in the area of Piedmont in particular, comprising the provinces of Alessandria, Asti, Novara and Vercelli, which is one of the most severely affected areas of the world, is emphasized. The evident increase in the number of cases in the last few years is a clear indication that it is an emergent zoonosis. CONCLUSIONS: We recommend that each and every case observed be recorded, to enable the true extent of human dirofilariasis in Italy to be assessed, and that a reference centre be set up in the area to collate the data. The importance of the histopathologist's role in the diagnosis is stressed.

A nodular pulmonary lesion due to Linguatula serrata in an HIV-positive man.

A coin-shaped pulmonary lesion was accidentally detected in a 42-year-old, HIV-seropositive man residing in Bari (Apulia, Southern Italy) during a routine X-ray examination. A lung cancer was suspected, obliging physicians to investigate surgically. After thoracotomy a lung nodule, 1.8 cm in diameter, was excised and submitted for histological examination. Histological analysis revealed a nodular infarctual lesion containing a larva of Pentastomida. Despite the poor state of preservation of the parasite it was possible to recognise some morphological characteristics which enabled the parasite to be identified as Linguatula serrata (Pentastomida, Porocephalida). This is the first case reported in Europe in the lung in a living man due to this parasite, the few others occurring in autopsy reports. No evident correlations were found in the present case between HIV-seropositivity and the development of the parasitosis. The importance of lung nodules caused by metazoan invertebrates is emphasised: even though they are rare in man, they are regularly mistaken for cancer at X-ray examination.

[Persistent scalp infestation by Dermanyssus gallinae in an Emilian country-woman]. / Infestazione persistente del cuoio capelluto da Dermanyssus gallinae in una contadina emiliana.

A case of persistent infestation of the scalp due to Dermanyssus gallinae.--Infestation due to Dermanyssus gallinae, the common red mite of poultry, in a country-woman aged 69 years from Crevalcore (Emilia-Romagna region, Northern Italy), is described. The case was unusual either for its location, the scalp, and for its persistence, 9 months. Specimens of the mite were also found in the henhouse adjacent to the patient's house. Apparently the woman recovered by means of daily washing of camomile tea.

Subconjunctival zoonotic Onchocerca in an Albanian man.

A case of subconjunctival infection with a zoonotic species of Onchocerca is described, in a 16-year-old Albanian man who had immigrated to Greece. This is the first report of human infection with Onchocerca in this tissue location and only the eighth report of zoonotic Onchocerca in man.

Human dirofilariasis due to Dirofilaria (Nochtiella) repens: an update of world literature from 1995 to 2000.

Following on from their review of 1995 (Pampiglione et al.), the authors present an update of human cases of dirofilariasis due to Dirofilaria (Nochtiella) repens (Nematoda, Filarioidea, Onchocercidae) reported in the world literature. Cases of the parasitosis published from 1995 to 2000 are reported country by country. The essential data are presented in tabular form and the clinical, parasitological, histopathological, epidemiological features are analysed. 372 new cases spread over 25 countries are thus added to the list published in 1995. The countries most affected are Italy, Sri Lanka, some republics of the ex-Soviet Union. The age of the patients varied from 4 months to 100 years, the majority being in their 40s. There was virtually no difference in incidence between sexes. The parasite appeared most frequently in the upper half of the body, particularly in the head and ocular region and also in the upper limbs. Cases of visceral involvement are also reported. Of the various forms of human dirofilariasis, that due to D. (N.) repens is confirmed to be the most important as regards not only the number of subjects affected and the wide geographical distribution but also the variety of organs involved, notably the lungs, the male genitals and the female breast, invariably leading to a wrong diagnosis of malignant tumour. In man, the zoonosis may be described as emerging: whereas until the middle of the last century only a few dozen cases were reported, in the last 50 years the number has gradually increased to reach the present 782.