Several outbreaks of trichinellosis associated with the consumption of raw pork have occurred in Laos since 2004. This cross-sectional study was conducted in four provinces of northern Laos to investigate the seroepidemiology of trichinellosis in the human population and determine the prevalence and species of Trichinella infection in the domestic pig population. Serum samples and questionnaire data were obtained from 1419 individuals. Serum samples were tested for Trichinella antibodies by ELISA using larval excretory–secretory (ES) antigens and a subset of 68 positive samples were tested by western blot. The seroprevalence of Trichinella antibodies was 19.1% (95% confidence interval (CI) = 17.1–21.1%). The risk of having antibodies detected by ELISA using ES antigens increased with age, being of Lao-Tai ethnicity, living in Oudomxay province and being male. Tongue and diaphragm muscle samples were collected from 728 pigs and tested for Trichinella larvae by the artificial digestion method. Trichinella larvae were isolated from 15 pigs (2.1%) of which 13 were identified as T. spiralis by molecular typing; the species of the two remaining isolates could not be determined due to DNA degradation. Trichinella spp. are endemic in the domestic environment of northern Laos and targeted preventative health measures should be initiated to reduce the risk of further outbreaks occurring.

The cestode Molicola horridus is a muscle parasite of teleost fish. The ability of molecules present in this parasite to induce allergic response is not known yet. Since fish-borne parasitic allergens can induce allergic manifestations even when the parasitized fish is well cooked, the knowledge of potential allergens present in food is important in order to provide a save products for consumers. The aim of the study was to determine the allergenic potential of the components present in the crude larval extract (CLE) of M. horridus. Two mouse models were exposed to the CLE: adult BALB/c mice that were intraperitoneally (i.p.) immunized and newborn BALB/c mice that were orally exposed. Specific antibody levels in serum and faeces were measured by ELISA. The cellular immune response was determined by proliferation assay of splenocytes from sensitized mice. The protein profile of CLE was analysed by SDS-PAGE and western blot. In adult mice, specific IgG and IgA were detected in sera and faeces, whereas specific IgE were detected in sera only. In newborn mice, specific IgG were detected in sera and a low level of IgA was detected in faeces. SDS-PAGE revealed the CLE protein profile, with most of the proteins running from 15 to 50kDa. Specific IgG recognized mainly the 26 and 75kDa proteins and a molecular complex below 100kDa by immunoblot. Specific IgE recognized the same 26kDa protein as IgG did, and, with less intensity, another protein at 30kDa. Splenocytes from CLE-immunized mice proliferated when stimulated with CLE in a dose-dependent manner. The crude larval extract from M. horridus has potential allergenic molecules which can represent a risk for fish consumers.

Abstract. We describe the diagnostic difficulties experienced during an opisthorchiasis outbreak. Of 31 infected individuals, 61.3% were asymptomatic, and in the 12 symptomatic individuals, the duration of non-pathognomonic symptoms was shorter than 4 weeks. Serology by enzyme-linked immunosorbent assay and polymerase chain reaction fecal analysis were shown to be the most sensitive diagnostic tools.Opisthorchiasis and clonorchiasis are zoonotic infections caused by liver flukes of the genera Opisthorchis and Clonorchis reported in Asia and Europe, where they affect an estimated 10 million people.1 However, most of the cases are from Asia, where the etiological agents are O. viverrini and C. sinensis. In Europe, the etiological agent is O. felineus, and cases of human infection have been documented in Byelorussia, Germany, Greece, Italy, Lithuania, Poland, Romania, Russia, Spain, and the Ukraine.2-5 Humans acquire the infection by consuming raw freshwater fish of the family Cyprinidae, which harbor the larval stage, metacercariae, in their muscles. 6 Because the clinical picture of infection depends on the number of fluke worms, persons who ingest a low number of parasites may have only mild or asymptomatic infection, 6,7 which could result in delayed or missed diagnosis. In fact, fluke parasites cannot multiply in the human body, and therefore, high fluke infection intensities can only be reached by repeated exposure to raw fish consumption. The importance of a timely diagnosis is in the fact that untreated infection can result in severe complications. In fact, in Asia, opisthorchiasis and clonorchiasis caused by a great number of O. viverrini and C. sinensis worms have been shown to cause cholangiocarcinoma, which can develop even 20 years after infection.1 In Italy, opisthorchiasis in humans was first reported in 2003, and since that time, a number of outbreaks have occurred. 5,8 In the present study, we describe an outbreak that occurred in 2009 to illustrate how diagnosis can be delayed when a high proportion of individuals have nonspecific symptoms or no symptoms at all.A case of opisthorchiasis was defined as the presence of opistorchidae eggs in feces and/or anti-Opisthorchis immunoglobulin G (IgG) in serum of persons who had consumed raw freshwater fish. Eggs were searched for in fecal samples after formol-ether concentration using a light microscope (150-400 + magnification). The fecal sediment was preserved in absolute ethyl alcohol for the molecular diagnosis and identification of the parasite. Parasite DNA was amplified by polymerase chain reaction (PCR) performed according to a published protocol.9 The 250-bp amplicon was sequenced and compared with the internal transcribed spacer 2 (ITS2) sequences of O. felineus, O. viverrini, and C. sinensis present in the GenBank database. Serology was performed with enzymelinked immunosorbent assay (ELISA) in accordance with a standard protocol using excretory/secretory (E/S) antigens from adult worms of O. felineus maintained in vitro.On March 15, 2010, a 46-...

The response of animals infected with different Trichinella species (T. spiralis, T. britovi, T. pseudospiralis) to antigens of different Trichinella species was evaluated in outbred mice (CD1) and inbred mice (BALB/c, C3H, SJL, C57BL/6). In mice deficient for IgE or IgG1, T. spiralis only was used. In homologous conditions (i.e., same Trichinella species for antigens and infectious agent) mortality was very high (up to 100% in SJL and C57BL/6). The anaphylactic response in heterologous conditions was much lower and death was observed only in C57BL/6 and SJL mice. Experiments with deficient mice have shown that both specific IgE and IgG1 independently induce a fatal anaphylactic response.

Trichinella spiralis and Trichinella pseudospiralis exhibit differences in the host-parasite relationship such as the inflammatory response in parasitized muscles. Several studies indicate that matrix metalloproteinases (MMPs) represent a marker of inflammation since they regulate inflammation and immunity. The aim of this study was to evaluate the serum levels of gelatinases (MMP-9 and MMP-2) in mice experimentally infected with T. spiralis or T. pseudospiralis, to elucidate the involvement of these molecules during the inflammatory response to these parasites. Gelatin zymography on SDS polyacrilamide gels was used to assess the serum levels and in situ zymography on muscle histological sections to show the gelatinase-positive cells. In T. spiralis infected mice, the total MMP-9 serum level increased 6 days post-infection whereas, the total MMP-2 serum level increased onward. A similar trend was observed in T. pseudospiralis infected mice but the MMP-9 level was lower than that detected in T. spiralis infected mice. Significant differences were also observed in MMP-2 levels between the two experimental groups. The number of gelatinase positive cells was higher in T. spiralis than in T. pseudospiralis infected muscles. We conclude that MMP-9 and MMP-2 are markers of the inflammatory response for both T. spiralis and T. pseudospiralis infections.