Ascariasis in Japan: is pig-derived Ascaris infecting humans?

~Content Source

Human ascariasis is caused by infection with the common roundworm Ascaris lumbricoides, although the pig roundworm Ascaris suum has also been reported to infect humans and develop into the adult stage. To elucidate whether pig-derived Ascaris infects humans in Japan, 9 Ascaris isolates obtained from Japanese patients and a further 9 Ascaris isolates of pig origin were analyzed to determine their internal transcribed spacer-1 sequences. Six of the 9 clinical isolates showed the Ascaris genotype which predominantly infects humans in endemic countries, while the other 3 clinical isolates and 9 pig-derived isolates showed the genotype predominant in pigs worldwide. These results suggest that at least some cases of human ascariasis in Japan are a result of infection with pig-derived Ascaris.

Ascaris suum, an Intestinal Parasite, Produces Morphine

~Content Source-The Journal of Immunology-J Immunol July 1, 2000, 165 (1) 339-343; DOI:


The parasitic worm Ascaris suum contains the opiate alkaloid morphine as determined by HPLC coupled to electrochemical detection and by gas chromatography/mass spectrometry. The level of this material is 1168 ± 278 ng/g worm wet weight. Furthermore, Ascaris maintained for 5 days contained a significant amount of morphine, as did their medium, demonstrating their ability to synthesize the opiate alkaloid. To determine whether the morphine was active, we exposed human monocytes to the material, and they immediately released nitric oxide in a naloxone-reversible manner. The anatomic distribution of morphine immunoreactivity reveals that the material is in the subcuticle layers and in the animals’ nerve chords. Furthermore, as determined by RT-PCR, Ascaris does not express the transcript of the neuronal μ receptor. Failure to demonstrate the expression of this opioid receptor, as well as the morphine-like tissue localization in Ascaris, suggests that the endogenous morphine is intended for secretion into the microenvironment.

Successful parasitism, in which the host survives for extended periods, can be characterized as an equilibrium between the parasite and the host, more specifically between the host’s immune system and the parasite’s ability to create a permissive microenvironment in situ. One mechanism that a parasite may use to modify the host immune response is to down-regulate the host’s response (123). Capron and colleagues (4567) suggested that parasites may communicate with their hosts via common signaling molecules that diminish host immune surveillance. In this regard, morphine is generally acknowledged as an immune down-regulating agent (8). This finding is enhanced by the fact that morphine is present in several mammalian tissues, including brain and adrenal gland (91011121314151617181920), supporting its role as a neural or inflammatory mediator.

Recently, we have demonstrated that free-living and parasitic invertebrates produce several major opioid peptide precursors, i.e., prodynorphin, proopiomelanocortin, and proenkephalin (21). These mammalian-like opioid peptides exhibit high sequence identity to their mammalian counterparts. For example, Mytilus adrenocorticotropin has greater than 90% sequence identity with its mammalian counterpart (21). We have also identified a tentative morphine-like molecule in Schistosoma mansoni by way of radioimmunoassay (22).

Given this and the fact that the pig intestinal parasite Ascaris suum can live in its host for extended periods of time, we surmised that it might be using morphine to escape detection by the host’s immune system. In this study, we report for the first time that A. suum synthesizes morphine, thereby strengthening the common-signal molecule hypothesis, i.e., using either similar or identical host signaling to escape host immunosurveillance.

Löffler’s syndrome

~Content Source – Wikipedia

Löffler’s syndrome is a disease in which eosinophils accumulate in the lung in response to a parasitic infection. The parasite can be Strongyloides stercoralisDirofilaria immitis[1] or Ascaris which can enter the body through contact with the soil.[2] The symptoms of Löffler’s syndrome include those of a parasitic infection such as irritable bowel syndrome, abdominal pain and cramping, skin rashes and fatigue. The Löffler’s syndrome itself will cause breathlessness, coughing as well as a fever.

In 1909 a man named H. French first described the condition.[8] Then in 1932 Wilhelm Löffler[1] drew attention to the disease in cases of eosinophilic pneumonia caused by the parasites Ascaris lumbricoides,[2]Strongyloides stercoralis and the hookwormsAncylostoma duodenale and Necator americanus. Finally in 1943 the condition was called Tropical eosinophilia by RJ Weingarten, and later officially named Löffler’s syndrome.[8] The most well-known case of Löffler’s syndrome was in a young boy from Louisiana. He arrived at the hospital reporting a high fever after three days, as well as having rapid breathing. ”He was hospitalized and treated with supplemental oxygen, intravenous methylprednisolone, and nebulized albuterol.”[9] The boy’s symptoms quickly subsided and upon further investigation it was discovered that the boy worked caring for pigs. A test was then performed on the pigs’ fecal matter and surrounding soil; it contained the parasite that had caused the boy’s ailment.

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