Human diphyllobothriosis in Taiwan: A review of cases and molecular evidence of Dibothriocephalus nihonkaiensis.

Diphyllobothriosis is an infectious disease caused by the consumption of raw freshwater or marine fish containing larvae of broad tapeworms (Diphyllobothriidae). In the present study, we critically reviewed all cases of human diphyllobothriosis reported from Taiwan, including unpublished reports from hospitals in Taipei. Genotyping based on mitochondrial DNA marker (cox1) confirmed that two of the recent cases were caused by Dibothriocephalus nihonkaiensis, which is not native to Taiwan and was probably imported with Pacific salmon infected with larvae of D. nihonkaiensis. The causative species previously reported in Taiwan could not be definitively confirmed. However, considering the distribution of Dibothriocephalus latus, which is not endemic in Taiwan, past cases diagnosed as D. latus are questionable.

Epidemiology, clinical features, and outcomes of strongyloidiasis in Taiwan from 1988 to 2020: A case series and literature review.

OBJECTIVES: We described a case of Strongyloides hyperinfection syndrome, reported a case series, and reviewed published cases of strongyloidiasis in Taiwan. METHODS: Confirmed cases of strongyloidiasis at the National Taiwan University Hospital (NTUH) and NTUH Hsin-Chu Branch from 1988 to 2020 were identified in the medical record database. Literature search was carried out through Pubmed, Google Scholar, and Index to Taiwan Periodical Literature System to identify published cases of strongyloidiasis in Taiwan from 1979 to 2020. Data pertaining to the demographics, underlying medical conditions, clinical manifestations, laboratory findings, and outcomes were extracted. RESULTS: A total of 117 cases of strongyloidiasis were identified, including 20 previously unpublished cases from the two hospitals and 97 published cases in the literature. Overall, 85 (73%) were male and the mean age was 64 years (range, 6-95 years). Classical symptoms such as diarrhea, cough, and skin rash were only observed in 43%, 37%, and 18% of the patients, respectively, whereas eosinophilia at presentation was only found in 48%. Strongyloides hyperinfection syndrome and disseminated strongyloidiasis were identified in 41 (35%) and 4 (3%) patients, respectively. Four (3%) patients had concurrent meningitis. In univariable analysis, being older and having pre-existing chronic obstructive pulmonary disease or asthma were associated with hyperinfection or dissemination (p = 0.024 and 0.003, respectively). The mortality rate was 43% among those with hyperinfection or disseminated infection. CONCLUSIONS: Strongyloidiasis can cause serious complications and mortality. Efforts to diagnose strongyloidiasis early are urgently needed to improve the outcome of patients with strongyloidiasis in Taiwan.

A RAB family antigen of Angiostrongylus cantonensis induces a Th1-type immune response in vitro and in vivo.

A cDNA library was constructed from an Angiostrongylus cantonensis young adult and the encoded proteins were expressed in Escherichia coli. One reactive antigen, a RAB-2 protein, was selected using an immunoscreening technique. The expression of the Th1-type cytokine IFN-γ was elicited in mouse splenic cells that were co-cultured with the recombinant RAB-2 protein and in the sera of mice that were immunised with this protein and adjuvant (50 µg at 2-week intervals). In the A. cantonensis-infected groups, the mice were orally infected with 35 infective larvae, and a subset of the infected mice were immunised with the recombinant RAB-2 protein in adjuvant. Serum samples were collected every week for ELISA, and the pathological examinations were performed at 14 days post infection (dpi). An increase in IFN-γ expression was noted in the blood, and the brain sections revealed moderate eosinophilic meningitis in the immunised mice. The RAB-2 antigen of A. cantonensis induced a Th1-type immune response both in vitro and in vivo.

Infectivity and development of Metagonimus yokogawai in experimentally infected domestic ducks (Cairina moschata).

Information concerning whether fowl such as duck is a suitable reservoir host of Metagonimus yokogawai is largely unclear to date. In the present study, the growth and development of M. yokogawai metacercaria (Mc) in domestic duck (Cairina moschata) was determined by worm recovery rate (WRR) and morphological changes e.g., the size of fluke's body as well as their internal organs was assessed by using Semichon's acetocarmine staining. Each duck was orally inoculated with 50 Mcs of M. yokogawai and infected ducks were deeply anesthetized with ether and killed at 1, 2, 3, 4, 5, 6, 7, and 14 days post-infection (DPI). On each date, two infected ducks were killed and the small intestines of each duck were separated into four parts then they were opened longitudinally to harvest the flukes. Results revealed that WRR of M. yokogawai from inoculated ducks increased during early infection with a peak as seen at 4 DPI (28.5+/-6.9%); thereafter it gradually decreased and a drastic decline was observed in 14 DPI (2.0+/-1.1%) in the trial. The preference sites for M. yokogawai were low portions of the small intestine; nevertheless the size of fluke's body and organs developed increasingly with time and they maturated to produce ova from 4 DPI onward in the trial. However, present results indicated that ducks, based on the findings of this study, are not suitable hosts for establishment of M. yokogawai infection because most flukes were expelled from duck's intestine within 14 days. Nevertheless, it was proposed that ducks might play a certain role in transmitting M. yokogawai when they deposited the ova via feces into marsh where snails and fish were abundant since they could presumably establish transient and possibly patent infections with this parasite.

Anti-CCR3 monoclonal antibody inhibits eosinophil infiltration in Angiostrongylus cantonensis-infected ICR mice.

ICR mice were each infected with 35 Angiostrongylus cantonensis larvae. One group of mice received an intraperitoneal injection of anti-CCR3 monoclonal antibody (mAb) (50 microg) at 10 days post-infection (dpi), while another similarly-treated group also received a booster injection (25 microg) at 12 dpi. All the mice were sacrificed at 14 dpi for pathological examination, enzyme-linked immunosorbent assay analysis and RNA extraction. The infiltration of eosinophils and the severity of eosinophilic meningitis were reduced in both the mAb-treated groups, relative to infected but untreated animals. The levels of CCL11 (eotaxin) in the peripheral circulation and the expression of the Th2-type cytokine interleukin-5 in the brains were significantly reduced. A. cantonensis infection is the major cause of eosinophilic meningoencephalitis in Taiwan, and the results of this study could be useful for the development of strategies to reduce the neurological damage caused by this infection.

Brain injury-associated biomarkers of TGF-beta1, S100B, GFAP, NF-L, tTG, AbetaPP, and tau were concomitantly enhanced and the UPS was impaired during acute brain injury caused by Toxocara canis in mice.

BACKGROUND: Because the outcomes and sequelae after different types of brain injury (BI) are variable and difficult to predict, investigations on whether enhanced expressions of BI-associated biomarkers (BIABs), including transforming growth factor beta1 (TGF-beta1), S100B, glial fibrillary acidic protein (GFAP), neurofilament light chain (NF-L), tissue transglutaminases (tTGs), beta-amyloid precursor proteins (AbetaPP), and tau are present as well as whether impairment of the ubiquitin-proteasome system (UPS) is present have been widely used to help delineate pathophysiological mechanisms in various BIs. Larvae of Toxocara canis can invade the brain and cause BI in humans and mice, leading to cerebral toxocariasis (CT). Because the parasitic burden is light in CT, it may be too cryptic to be detected in humans, making it difficult to clearly understand the pathogenesis of subtle BI in CT. Since the pathogenesis of murine toxocariasis is very similar to that in humans, it appears appropriate to use a murine model to investigate the pathogenesis of CT. METHODS: BIAB expressions and UPS function in the brains of mice inoculated with a single dose of 250 T. canis embryonated eggs was investigated from 3 days (dpi) to 8 weeks post-infection (wpi) by Western blotting and RT-PCR. RESULTS: Results revealed that at 4 and 8 wpi, T. canis larvae were found to have invaded areas around the choroid plexus but without eliciting leukocyte infiltration in brains of infected mice; nevertheless, astrogliosis, an indicator of BI, with 78.9~142.0-fold increases in GFAP expression was present. Meanwhile, markedly increased levels of other BIAB proteins including TGF-beta1, S100B, NF-L, tTG, AbetaPP, and tau, with increases ranging 2.0~12.0-fold were found, although their corresponding mRNA expressions were not found to be present at 8 wpi. Concomitantly, UPS impairment was evidenced by the overexpression of conjugated ubiquitin and ubiquitin in the brain. CONCLUSION: Further studies are needed to determine whether there is an increased risk of CT progression into neurodegenerative disease because neurodegeneration-associated AbetaPP and phosphorylated tau emerged in the brain.

Enhanced expression of transforming growth factor-beta 1 in inflammatory cells, alpha-smooth muscle actin in stellate cells, and collagen accumulation in experimental granulomatous hepatitis caused by Toxocara canis in mice.

Although toxocaral granulomatous hepatitis (TGH) characterized with a dominant-Th2 type immune response is a self-limiting disease, little is known concerning the role of fibrosis-related cytokine transforming growth factor-beta 1 (TGF-beta 1) in pathogenesis of TGH. A detailed histological and quantitatively immunohistochemical analysis of TGF-beta 1, alpha-smooth muscle actins (alpha-SMA), and collagen was performed on the liver tissues from mice infected with Toxocara canis as assessed between day 1 and 42 weeks post-infection (DPI or WPI). TGF-beta1 was detected mainly in infiltrating leukocytes in lesions with strong expressions from 4 to 16 WPI. Larvae per se also exhibited strong TGF-beta 1-like molecule expressions in the trial. Alpha-SMA was detected predominantly in hepatic stellate cells (HSC) which surrounded the lesions with moderate expressions largely throughout the period of the entire experiment. Collagen was observed to accumulate in inflammatory lesions and biliary basement with moderate to strong expressions from 1 WPI onwards in the trial. Since many evidences have indicated that leukocytes have the potential to influence HSC by producing TGF-beta 1 which can affect HSC to increase collagen synthesis in various liver diseases, we may propose that persistently elevated TGF-beta 1 expression in infiltrating leukocytes and active HSC with marked alpha-SMA expressions may contribute to healing of injured sites through up-stimulation of collagen deposition; in contrast, abnormally persistent collagen accumulation may cause irreversible fibrotic injury in the TGH.

Suppression of host Th1-type granulomatous inflammation by Taenia solium metacestodes is related to down-regulation of osteopontin gene expression.

Inflammation and granuloma formation in human neurocysticercosis has been attributed to Th1-type immune responses of the host. In the present murine model, over 94% of Taenia solium metacestodes were viable and elicited no granulomatous inflammation, whereas parasites killed by praziquantel treatment elicited rapid granuloma formation that calcified within 2weeks. Osteopontin (OPN) is a Th1-related cytokine that is up-stream of IL-12 and which may play an essential role in granuloma formation and calcification. OPN mRNA expression was down-regulated in tissues surrounding viable cysticerci, but was up-regulated in inflammatory tissues surrounding degenerating cysticerci. Moreover, co-culture with a viable cysticercus or ES products from these metacestodes led to a decrease in OPN, IFN-gamma and IL-12 expression, whereas co-culture with somatic proteins enhanced OPN expression by leukocytes. Addition of recombinant mouse OPN (rmOPN) counteracted the down-regulation of IL-12 and IFN-gamma mRNA expression, but not OPN mRNA expression, in leukocyte cultures. Furthermore, injection of rmOPN into the tissues surrounding implanted cysticerci enhanced inflammatory responses while a similar injection of an anti-rmOPN antibody reduced inflammation. These findings suggest that the suppression of host Th1-type granulomatous inflammation by ES products from T. solium metacestodes is related to down-regulation of OPN gene expression.

Seroprevalence of Toxoplasma gondii infection among inhabitants in the Democratic Republic of Sao Tome and Principe.

The level of Toxoplasma gondii infection among the general population of the Democratic Republic of Sao Tome and Principe is unclear. The T. gondii infection status of inhabitants who visited National Central Hospital on Sao Tome Island was assessed by a latex agglutination test. The overall seroprevalence was 74.5% (120/161). No significant gender difference in seroprevalence was found between males and females. The older age group (> or =45 years) had significantly higher seroprevalence (80.0%, 28/35) than the younger age group (<15 years) (20.0%, 3/15) (chi(2)=16.04, P<0.001).

Prevalence of intestinal infection due to Cryptosporidium species among Taiwanese patients with human immunodeficiency virus infection.

BACKGROUND/PURPOSE: Cryptosporidiosis causes significant morbidity and mortality in human immunodeficiency virus (HIV)-infected patients who do not receive highly active antiretroviral therapy. Related data on cryptosporidiosis in Taiwanese HIV-infected patients are very limited. This study assessed the prevalence of intestinal infection due to Cryptosporidium spp. among Taiwanese patients with HIV infection. METHODS: This retrospective review included 1044 patients with HIV infection treated between June 1994 and June 2004. Intestinal colonization due to Cryptosporidium spp. was identified by polymerase chain reaction and restriction fragment length polymorphism of stool specimens collected from 332 of the HIV-infected patients without gastrointestinal symptoms, 90% of whom were receiving highly active antiretroviral therapy. RESULTS: Five out of 1044 (0.5%) HIV-infected patients had a diagnosis of intestinal cryptosporidiosis by endoscopic biopsy or examinations of stool specimens. Intestinal colonization due to Cryptosporidium spp. was found in four of 332 (1.2%) asymptomatic HIV-infected patients between 2001 and 2003; two were due to C. hominis, and one each were due to C. felis and C. meleagridis. CONCLUSION: Our findings indicate that the prevalence of intestinal colonization due to Cryptosporidium is low among HIV-infected patients in Taiwan.

Serological screening and toxoplasmosis exposure factors among pregnant women in the Democratic Republic of Sao Tome and Principe.

The seroprevalence of Toxoplasma gondii infection among pregnant women in the Democratic Republic of Sao Tome and Principe (DRSTP) from November 2003 to March 2004 was determined by detection of serum anti-T. gondii antibodies. A short questionnaire interview for pregnant women was performed to investigate risk factors associated with T. gondii infection, including consumption of raw meat or unwashed vegetables, drinking unboiled water and keeping pets (cats and dogs). The overall seroprevalence of T. gondii infection was high (75.2%; 375/499). The older age group of > or =35 years had a significantly higher seroprevalence (85.7%; 54/63) than that of the younger age group of 15-25 years (70.4%; 178/253) (odds ratio 2.5, 95% CI 1.2-5.4; P=0.01). No significant difference in the seroprevalence of T. gondii infection was found between the pregnant women with and without exposure to the risk factors studied. However, among pregnant women with high antibody titers of > or =1:1024, it seemed likely that continual contact with pets and consumption of oocyst-contaminated water or raw unwashed vegetables rather than tissue cysts in meat was the primary route of infection. The incidence of congenital toxoplasmosis in unborn babies should be intensively monitored in the DRSTP.

Angiostrongylus cantonensis: apoptosis of inflammatory cells induced by treatment with mebendazole or/and interleukin 12 in mice.

Angiostrongylus cantonensis is the major cause of human eosinophilic meningoencephalitis. ICR mice were infected orally with 35 infective larvae and sacrificed at 4-14 days, 25 days or 32 days post infection (dpi) for pathological and immunocytochemical examinations. In the non-treated group, no apoptosis signal was found in the meninges or parenchyma of the brains (4-14 dpi). Only a few apoptotic cells were noticed at 25 dpi (3%) and 32 dpi (10%). In the groups, the animals were given a single dose of mebendazole (20 mg/kg, per os at various times) or injections of interleukin 12 (IL-12) (10 ng/daily, intraperitoneally), all the animals were sacrificed at 14 dpi; the number of apoptotic cells was increased (17-21%). In the group that received a single dose of mebendazole (4 dpi) in combination with IL-12 injections (4-13 dpi), mild meningitis was observed, and most of the infiltrated inflammatory cells were in the apoptotic program (55%). Taken together, apoptosis of the inflammatory cells (most were eosinophils) could be induced when the infected mice were treated with mebendazole or/and IL-12.

Trichomonas empyema with respiratory failure.

Pulmonary trichomoniasis is rare, and few cases of trichomonas empyema have been reported in the literature. We describe a rare case of a non-immunocompromised 55-year-old man with Trichomonas empyema presenting with bilateral pleural effusion leading to respiratory failure. Examination of the pleural effusion showed numerous motile organisms by fresh wet preparation that were identified as Trichomonas species by Liu stain. The patient was successfully treated with metronidazole, ampicillin/clavunalate, fibrinolytic therapy, and thoracotomy decortication.

Seroprevalence of Toxoplasma gondii infection among pre-schoolchildren aged 1-5 years in the Democratic Republic of Sao Tome and Principe, Western Africa.

The prevalence status of Toxoplasma gondii infection in children of the Democratic Republic of Sao Tome and Principe (DRSTP), Western Africa, is unknown to date. A serologic survey of T. gondii infection among pre-schoolchildren aged <5 years in the DRSTP was assessed by the latex agglutination (LA) test from November 2003 to March 2004. The overall seroprevalence of T. gondii infection was not low, reaching 21.49% (26/121). No significant gender difference in seroprevalence was found between boys (19.30%; 11/57) and girls (23.44%; 15/64) (chi2 = 0.31, P = 0.58). The older age group of 4-5 years had significantly higher seroprevalence (36.67%; 11/30) than the younger age group of <2 years (10.34%; 3/29) (chi2 = 5.64, P = 0.02). It was noteworthy that the majority of seropositive boys (90.91%; 10/11) or older children aged > or = 2 years (82.61%; 19/23) had high LA titres of > or = 1:1024, indirectly indicating acute Toxoplasma infection. This study is the first report indicating that T. gondii infection is not low in pre-schoolchildren aged <5 years in the DRSTP. Whether the DRSTP pre-schoolchildren acquire T. gondii infection through constant exposure to the parasite from their daily activities owing to poor environmental hygiene should be further evaluated.

Invasive amebiasis as an emerging parasitic disease in patients with human immunodeficiency virus type 1 infection in Taiwan.

BACKGROUND: Whether risk of invasive amebiasis due to Entamoeba histolytica is higher among human immunodeficiency virus (HIV)-infected persons than uninfected persons remains unclear, although intestinal colonization by Entamoeba dispar is common among men who have sex with men. Our objective was to determine the prevalence of invasive amebiasis and intestinal colonization by E histolytica and E dispar in HIV-infected persons and uninfected controls. METHODS: We assessed the prevalence of invasive amebiasis by case review of 951 HIV-infected persons and by serologic studies of 634 of the 951 HIV-infected persons, 429 uninfected controls with gastrointestinal symptoms, and 178 uninfected healthy controls using indirect hemagglutination antibody assay. We assessed the rate of intestinal colonization by E histolytica and E dispar by fecal antigen and polymerase chain reaction tests in 332 asymptomatic HIV-infected persons and 144 of the 178 uninfected healthy controls. RESULTS: Forty-nine (5.2%) of 951 HIV-infected persons had 51 episodes of invasive amebiasis. A high indirect hemagglutination antibody titer was detected in 39 (6.2%) of 634 HIV-infected persons compared with 10 (2.3%) of 429 uninfected controls with gastrointestinal symptoms and 0 of 178 uninfected healthy controls (P<.001). Stool specimens from 40 (12.1%) of 332 HIV-infected persons and 2 (1.4%) of 144 uninfected healthy controls were positive for E histolytica or E dispar antigen (P<.001). Ten (25.0%) of the 40 antigen-positive stool specimens from HIV-infected persons contained E histolytica. CONCLUSION: Persons infected with HIV in Taiwan are at increased risk for invasive amebiasis and exhibit a relatively high frequency of elevated antibody titers and intestinal colonization with E histolytica.

Seroepidemiology of Toxocara canis infection among mountain aboriginal schoolchildren living in contaminated districts in eastern Taiwan.

We conducted a seroepidemiological study of Toxocara canis infection among mountain aboriginal schoolchildren aged 7-12 years living in contaminated districts in eastern Taiwan. To detect sera IgG (> or =1:64) we used a T. canis larval excretory-secretory antigen-based enzyme-linked immunosorbent assay. A short questionnaire elicited information on the practices of raising dogs, playing with soil, eating raw vegetables, or whether the child normally washed his/her hands before eating. The overall seroprevalence was quite high, reaching 76.6% (252/329). Neither age nor gender seemed to be important factors related to a positive serology. Aboriginal schoolchildren who raised dogs (OR=1.83, 95% CI: 1.04-3.19, P=0.03), or played with soil (OR=2.52, 95% CI: 1.49-4.25, P <0.001) seemed to be more susceptible to T. canis infection than those who did not. Children who habitually washed their hands before eating (OR=0.57, 95% CI: 0.33-0.97, P=0.04) had a lower chance of acquiring T. canis infection than those who did not.

Enhanced expression of transforming growth factor-beta1 in inflammatory cells and secretory granules in Paneth cells in the small intestine of mice infected with Toxocara canis.

The small intestine is the initial organ which Toxocara canis larvae invade. Information on intestinal pathological changes associated with transforming growth factor-beta1 (TGF-beta1) and secretory granules (SG) in Paneth cells (PCs) caused by T. canis is unclear. Mice orally inoculated with 250 T. canis infective eggs were evaluated by pathological and immunohistochemical assessments with a 294-day investigation. Pathologically, the inflammatory reactions with or without trapped larvae in the submucosa were observed only within the first 28 days post-infection (DPI), with inflammatory injury ranging from severe during 2 DPI to mild between 7 and 28 DPI. The crypts of Leiberkuhn were major larval penetration sites. Enhanced expression of SG in PCs appeared earlier than those of TGF-beta1 in infiltrating cells. The significance of both effectors might be related to the host's defense against larval invasion in the intestinal phase of toxocaral infection.

Cross-reactions with Ascaris suum antigens of sera from mice infected with A. suum, Toxocara canis, and Angiostrongylus cantonensis.

Ascaris suum larval excretory-secretory (AsES) antigen and larval (AsLA) as well as adult somatic antigen (AsAA) which were thought to be possibly helpful in the diagnosis of visceral larva migrans (VLM) due to A. suum infection were investigated in the present study. Serum taken from mice orally inoculated with approximately 250 embryonated eggs of A. suum or Toxocara canis, or 40 third-stage larvae of Angiostrongylus cantonensis were assessed by enzyme-linked immunosorbent assay (ELISA) using the AsES antigen, AsLA or AsAA at 1, 2, 3, 4, 6 and 8 weeks post infection (WPI). The titer of serum IgG from mice infected with A. suum increased from 1 WPI and a peak at 4 WPI was observed when it reached approximately three times the level of uninfected control mice. Thereafter, it decreased gradually but remained high as found from 6 to 8 WPI. No cross-reactions of heterologous serum IgG against AsES antigen was observed, whereas heterologous serum IgM exhibited significant cross-reactions to AsES antigen. Cross-reactivities to AsLA and AsAA by heterologous serum IgG as well as IgM antibodies were also observed in the trial. Altogether, the AsES antigen apparently seemed to be superior to the other two somatic antigens when used in the diagnosis of A. suum-induced VLM with serum IgG as tested by ELISA. Moreover, it was the first report to test the possibly antigenic cross-reactivity between A. suum and A. cantonensis.