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ABSTRACT: The organ distribution of Toxocara cati larvae in albino rats Rattus norvegicus (n=6/group) experimentally inoculated with 1000 embryonated eggs was examined 1, 2, 3, 7, 30, 90, and 180 days post inoculation (dpi), and the infectivity of recovered larvae was evaluated by bioassay in mice. The intestines, liver, lungs, muscles (carcass) and other organs (heart, brain, spleen, kidneys and genital organs) were digested for larval recovery. Larvae were recovered from all rats, with the mean number of recovered larvae ranging from 13.3 at 1dpi to 135.6 at 90dpi. Most of the larvae recovered were detected in the intestines (56.3%) and liver (43.8%) at 1dpi; liver (21.6%) and lungs (69.6%) at 2dpi; muscles (45.9%) and lungs (36.9%) at 3dpi. Subsequently, most of larvae were recovered from muscles at 7dpi (92.5%), 30dpi (97.8%), 90dpi (99.4%) and 180dpi (99.1%). In the mouse bioassay, 43.8% of 90-day-old larvae and 43.0% of 180-day-old larvae recovered from rats established in mice. The present study demonstrated that T. cati larvae persist predominantly in rat muscles and nearly half of them retain infective for at least half a year. The results indicate that R. norvegicus may be a suitable paratenic host of T. cati under natural conditions.
Veterinary Parasitology 03/2013; · 2.58 Impact Factor
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ABSTRACT: Infectivity of Toxocara cati larvae in muscle tissue of chickens after storage at 4°C and -25°C was assessed in a mouse bioassay to provide information on the risk of meat-borne toxocarosis. Muscle tissue samples of 30-day old T. cati infections were stored at 4°C for 14 and 28 days and at -25°C for 12, 24 and 48h, whereafter, larvae were released by digestion. For each experimental group, the released larvae were inoculated in six mice. After 15 days, mice were euthanized and larval burden was assessed by digestion. In the control group (no storage of the infected chicken meat), 47.9% of the inoculated larvae established in mice, whereas storage of meat at 4°C for 14 days or 28 days reduced the recovery to 24.1% or 3.3%, respectively. Muscle larvae exposed to -25°C for 12, 24 or 48h did not establish in the mice. The observation that larvae retain infective after refrigeration at exposure in 4°C for 28 days, emphasize the zoonotic potential of poultry meat as a causative agent of human toxocarosis.
Veterinary Parasitology 05/2012; 189(2-4):383-6. · 2.58 Impact Factor
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ABSTRACT: The distribution of Toxocara cati larvae in the organs of chickens (n=31), experimentally inoculated with 3000 embryonated eggs, was examined 1, 2, 3, 7, 29, 86 and 175-176 days post-infection (dpi), and the infectivity of recovered larvae was evaluated by bioassay in mice. The duodenum, liver, lungs, heart, brain, pectoral muscles (white meat), and hindlimb muscles (red meat) of the chickens were HCl-pepsin digested for larval recovery. Larvae were recovered from all chickens [mean=220.4 ± 114.9 (SD)], and although no decrease of total larval recovery was observed over time, predilection sites changed: liver (92.6% of larval recovery) at 1 dpi; lungs (77.3%) and liver (20.9%) at 2 dpi; lungs (80.8%), muscles (9.4%), and liver (8.5%) at 3 dpi; muscles (52.0%) and lungs (45.6%) at 7 dpi, whereafter most larvae were recovered from muscles: 29 dpi (99.5%), 86 dpi (99.3%) and 175-176 dpi (99.6%). In the bioassay, 52.9% of larvae from 175 to 176 days old infections in chickens established in mice, which demonstrates that T. cati larvae retain infective in the muscles of chickens for half a year. These results highlight the zoonotic potential of poultry meat as a causative agent of human toxocarosis.
Veterinary Parasitology 03/2011; 180(3-4):287-91. · 2.58 Impact Factor
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ABSTRACT: In order to develop an inexpensive, simple, and accurate method of monitoring for the reemergence of schistosomiasis japonica in Yamanashi Prefecture, Japan, the distribution and habitation density of the intermediate host, Oncomelania nosophora, were spatially analyzed using geographic information systems. The 1967-1968 density distribution maps prepared by Yamanashi Prefecture and Nihei were digitized and geocoded. The habitats and population density of O. nosophora were estimated by referring to the data compiled by the Yamanashi Association for Schistosomiasis Control (1977). These earlier findings were compared with average population densities between 1996 and 2000 previously recorded (Nihei, N., Kajihara, N., Kirinoki, M., et al., Parasitol. Int., 52, 395-401, 2003 and Nihei, N., Kajihara, N., Kirinoki, M., et al., Parasitol. Int., 53, 199-205, 2004). A variance map was created to compare the spatial distribution maps of population density from each of the two periods of interest. The changes in distribution were remarkable and the map was found to be effective for future control. The most appropriate monitoring sites were chosen on the basis of the spatial population density maps and the variance map. Moreover, the paddy fields at risk were extracted using the normalized difference vegetation index value based on Advanced Land Observation Satellite images. The combination of this method with the global positioning system provides an inexpensive means of monitoring modern schistosomiasis endemic areas in Japan and also in China, the Philippines, and other countries as well, where the intermediate snail grows in paddy fields and marshlands under consistently wet conditions.
Japanese journal of infectious diseases 04/2009; 62(2):125-32. · 1.49 Impact Factor
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ABSTRACT: A new, convenient method was developed to supply CO2 for mosquito sampling by using yeast, which converts sugar into CO2 and ethyl alcohol. The system could, at average, generate 32.4 ml/min of CO2 for at least 27 h. The total weight of the CO2 generated was estimated to be 94 g. The efficacy of yeast-generated CO2 as attractant for mosquitoes was significant, and the following 6 mosquito species were collected using yeast-generated CO2 traps from July to September 2003 in a residential area of southern and northern Yokohama City, Japan: Aedes albopictus (Skuse), Armigeres subalbatus (Coquillett), Culex halifaxii Theobald, Cx. pipiens pallens Coquillett, Ochlerotatus japonicus (Theobald), and Tripteroides bambusa (Yamada). Besides mosquitoes, various other insects were collected in the trap. Species compositions of insects collected in yeast-generated CO2 traps and dry-ice-baited traps were compared.
Journal of the American Mosquito Control Association 10/2004; 20(3):261-4. · 0.91 Impact Factor
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ABSTRACT: There are still many Oncomelania snails that inhabit the Kofu Basin, Yamanashi Prefecture, Japan, which had been declared free of schistosomiasis japonica. Due to the need to monitor the situation, a fixed-point observation system using GIS from GPS is being examined. In addition, in broad present or former endemic areas, survey areas are being managed by remote sensing with satellite images or aerial photographs. A simple and effective monitoring method by mobile GIS using PDAs was developed, risk or hazard maps were prepared and a system that would enable a response in the event of reemergence is being examined.
Parasitology International 07/2004; 53(2):199-205. · 2.13 Impact Factor
