Epidemiology of concomitant infection due to Loa loa and Mansonella perstans in Gabon.

BACKGROUND: The filarial parasites Loa loa and Mansonnella perstans are endemic in the central and western African forest block. Loa loa is pathogenic and represents a major obstacle to the control of co-endemic filariae because its treatment can cause fatal complications such as encephalitis. METHODOLOGY/PRINCIPAL FINDINGS: 4392 individuals aged over 15 years were studied both by direct examination and a concentration technique. The overall prevalence rates were 22.4% for Loa loa microfilaremia, 10.2% for M. perstans microfilaremia, and 3.2% for mixed infection. The prevalence of both filariae was higher in the forest ecosystem than in savannah and lakeland (p<0.0001). The intensity of microfilariae (mf) was also higher in the forest ecosystem for both parasites. The prevalence and intensity of microfilaria were both influenced by age and gender. Correlations were found between the prevalence and intensity of Loa loa microfilariae (r = 0.215 p = 0.036), and between the prevalence of Loa loa and the prevalence of individuals with microfilaria >8000 mf/ml (r = 0.624; p<0.0001) and microfilariae >30 000 mf/ml (r = 0.319, p = 0.002). In contrast, the prevalence of pruritis and Calabar swellings correlated negatively with the prevalence of Loa loa microfilaria (r = -0.219, p = 0.032; r = -0.220; p = 0.031, respectively). Pruritis, Calabar swellings and eye worm were not associated with L. loa mf intensity (r = -0.144, p = 0.162; r-0.061, p = 0.558; and r = 0.051, p = 0.624, respectively), or with the prevalence or intensity of M. perstans microfilariae. CONCLUSIONS/SIGNIFICANCE: This map of the distribution of filariae in Gabon should prove helpful for control programs. Our findings confirm the spatial uniformity of the relationship between parasitological indices. Clinical manifestations point to a relationship between filariae and allergy.

[Loa Loa and Mansonella perstans coinfection in a patient from Guinea]. / Coinfección por dos filarias (Loa loa y Mansonella perstans) en una paciente proveniente de Guinea.

We present a case of mixed infection by two filariae (Loa loa and Mansonella perstans). It seems that the infection was suspected due to a pronounced eosinophilia in a routine analysis. Sheathed and unsheathed microfilariae were observed in the spread of peripheral blood, which enabled a diagnosis to be established of mixed infection by filariae. The definitive diagnosis of the species was carried out at the National Centre of Microbiolgy of Majadahonda. A treatment was initiated with dietilcarbamazina and mebendazole which resulted in the patient's being cured and in the elimination of the microfilariae in the patient's blood. Filariasis is still endemic in many countries. Due to the increase of travellers to such zones and the migratory movements from such areas it is not unusual for us to come across such a diagnosis. The implantation of massive treatments against filariae in endemic zones by the World Health Organisation is reducing their transmission and is managing to eliminate the disease in some areas.

The potential of mice as animal models for antifilarial screening.

Transplanted infections of Brugia pahangi and Dipetalonema viteae in male BALB/c and CDI mice were investigated as models for evaluating potential antifilarial compounds. The physiology and genetics of the above mouse strains are better defined than any of the rodent species currently used for primary in vivo screening, facilitating a more reproducible means for predicting the filaricidal activity of compounds. The recoveries of B. pahangi macrofilariae, implanted intraperitoneally were greater than or equal to 50% up to six weeks after implant in both CDI and BALB/c mice. The recoveries of D. viteae macrofilariae, implanted subcutaneously, were greater than 50% up to four weeks post implant but had fallen to less than 30% by six weeks. The survival of B. pahangi and D. viteae macrofilariae simultaneously implanted into mice mimicked that seen with the mono-infections, but significantly better recoveries were obtained from dual implanted CDI mice compared to the BALB/c mice when the numbers of macrofilariae implanted were varied. Standard antifilarials were evaluated against D. viteae and B. pahangi dual implanted into either CDI mice or gerbils. The mouse dual implant detected significant worm reductions against D. viteae, B. pahangi or both with all antifilarials tested except CGP 6140. Similarly under the test conditions CGP 6140 was not detected in the gerbil assay, but there were marked differences in the results obtained with the mice and gerbil models. The reasons for these differences are discussed.

[Filarial multiparasitism in the savannah zone in Burkina Faso]. / Etude du polyparasitisme filarien en zone de savane au Burkina Faso.

From june 1985 to may 1986, 1.209 consulting patients were examined for filariae in skin and blood. Among patients with microfilariae 17% had associations of filarial infections. The multiple infections rate seemed more important in man than woman and increased with age. The results showed that associations were not due to chance only. The frequencies of associations between Dipetalonema perstans and Onchocerca volvulus at one hand, Dipetalonema perstans and Wuchereria bancrofti on the other hand were highly significant. Symptoms of filarial associations were studied and subsequent therapeutic attitude discussed.

Courses of infections with Plasmodium falciparum in own monkeys displaying a microfilaremia.

Infections with the Uganda Palo Alto, Malayan Camp-CH/Q, Vietnam Oak Knoll, and Vietnam Smith strains of Plasmodium falciparum in owl monkeys (Aotus trivirgatus griseimembra) with concomitant microfilaremias usually, but not always, followed a more benign course than infections with the same strains in monkeys free of filarial infections. Four distinct microfilariae were identified in systematic examinations of 26 monkeys, 5 with self-limited infections with P. falciparum, 9 with normally benign self-limited infections with P. vivax, and 12 without previous malaria. The microfilariae found included: Dipetalonema (Dipetalonema) gracile, Tetrapetalonema (Tetrapetalonema) barbascalensis, T. (T.) panamensis, and an unidentified species designated "Aotus C." Among 23 monkeys studied completely, 14 were infected with a single species, 4 had double infections, and 5 had triple infections. T. barbascalensis was identified in 16 monkeys, T. panamensis in 11. Although data were very limited, there was a suggestion that infections with P. falciparum were less intense in monkeys infected with T. barbascalensis, either alone or with other filariae, than in subjects infected only with T. panamensis.

[Simultaneous infection of Mastomys natalensis with Dipetalonema witei and Litomosoides carinii (author's transl)]. / Simultane Infektion mit Dipetalonema witei und Litomosoides carinii bei Mastomys natalensis.

Mastomys natalensis that has been described by Lämmler et al. (1968) as suitable host for Litomosoides carinii can also serve as final host for Dipetalonema witei. At the end of the prepatency period the microfilaraemia increased as rapidly in Mastomys as in the original final host Meriones persicus. Maximal microfilaraemia was observed earlier in Mastomys (120 days p.inf.) than in Meriones (250 days p.inf.). Accordingly microfilariae counts decreased more rapidly in Mastomys. The maximal counts found in Mastomys was 78000 microfilariae/ml blood, which is 3.2 times less than in M. persicus. Furthermore it could be demonstrated that a simultaneous experimental infection of Mastomys with D. witei and L. carinii in possible. The course of microfilaraemia and the number of macrofilariae were comparable in mono- and simultaneous infections for both species of filariae. The macrofilariae of D. witei began to die earlier than those of L. carinii both in mono- and in simultaneous infections. The percentage of dead macrofilariae was 3.8% 110 days p.inf., and 13.1% 130 days p.inf. respectively. Therefore, chemotherapeutic experiments should be terminated and evaluated about 110 days p.inf.

Amyloidosis induced in hamsters by a filarid parasite (Dipetalonema viteae).

Amyloidosis was induced in hmasters infected with the filarial nematode parasite, Dipetalonema viteae. The incidence of amyloidosis was 64% in a group inoculated with 150 larvae and 54% in the group receiving 150 larvae in each of two inoculations. Amyloidosis was not seen in control animals. Microfilariae probably served as the antigenic stimulus in the pathogenesis of amyloidosis, since those animals in which amyloidosis was formed had microfilaremias that were significantly greater (P less than 0.05) both in number and duration than those in infected animals that did not develop amyloidosis. Other reports of amyloidosis associated with filariasis are reviewed.