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Diagnosis of human visceral pentastomiasis.

Tappe D, Büttner DW - PLoS Negl Trop Dis (2009)

Bottom Line: In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis.Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations.This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany. dtappe@hygiene.uni-wuerzburg.de

ABSTRACT
Visceral pentastomiasis in humans is caused by the larval stages (nymphs) of the arthropod-related tongue worms Linguatula serrata, Armillifer armillatus, A. moniliformis, A. grandis, and Porocephalus crotali. The majority of cases has been reported from Africa, Malaysia, and the Middle East, where visceral pentastomiasis may be an incidental finding in autopsies, and less often from China and Latin America. In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis. Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations. This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.

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Different types of tissue reactions of human patients to vital, degenerated, and nearly absorbed pentastome nymphs.(A) Viable nymph (ny) of A. armillatus with thin fibrous capsule in the lung. (B) Three cross sections of one viable A. armillatus in the intestinal wall with very little cellular reaction. (C) Body wall of a well-preserved vital nymph (ny) of A. armillatus in the liver with exuvia (arrow), a thick fibrous capsule, and moderate infiltration of the adjacent liver tissue. (D) Dead and degenerated A. armillatus in a lymph node with a thick fibrous capsule. (E) Linguatula nodule with target-like appearance in human lung. In the center of the nodule, a dead degenerated nymph (ny) is visible. Due to the coiled shape of the nymph, two adjacent fibrous rings are discernable on this section. (F) Granulomatous scar with central amorphous mass in the lung. Remnants of the cuticle (arrow) of L. serrata are still left. Scale bars: (C) = 100 mm; all others = 500 µm. Hematoxylin and eosin (B); trichrome stain (all others).
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pntd-0000320-g005: Different types of tissue reactions of human patients to vital, degenerated, and nearly absorbed pentastome nymphs.(A) Viable nymph (ny) of A. armillatus with thin fibrous capsule in the lung. (B) Three cross sections of one viable A. armillatus in the intestinal wall with very little cellular reaction. (C) Body wall of a well-preserved vital nymph (ny) of A. armillatus in the liver with exuvia (arrow), a thick fibrous capsule, and moderate infiltration of the adjacent liver tissue. (D) Dead and degenerated A. armillatus in a lymph node with a thick fibrous capsule. (E) Linguatula nodule with target-like appearance in human lung. In the center of the nodule, a dead degenerated nymph (ny) is visible. Due to the coiled shape of the nymph, two adjacent fibrous rings are discernable on this section. (F) Granulomatous scar with central amorphous mass in the lung. Remnants of the cuticle (arrow) of L. serrata are still left. Scale bars: (C) = 100 mm; all others = 500 µm. Hematoxylin and eosin (B); trichrome stain (all others).

Mentions: In human patients, three types of pentastomid lesions have been described histologically [8],[11],[21]. In the first type, a viable nymph (Figures 5A–5C) is found in a cyst with little or no adjacent cellular infiltration of the host tissue, since the living nymph excretes only small amounts of antigenic compounds. Surrounding the parasite, usually a thin layer of homogenous, refractile, eosinophilic material of the exuvia is seen (Figures 5C and 5D, [24]). A narrow zone of epitheloid cells may adjoin the fibrous capsule (Figure 5C), peripheral to which are macrophages and, rarely, a few giant cells and lymphocytes. Usually only few or no eosinophils are seen [21]. Based on the morphology of the nymph, pentastomiasis can be diagnosed etiopathologically [11], and usually the pentastome genus or family can be identified in lesions of this type.


Diagnosis of human visceral pentastomiasis.

Tappe D, Büttner DW - PLoS Negl Trop Dis (2009)

Different types of tissue reactions of human patients to vital, degenerated, and nearly absorbed pentastome nymphs.(A) Viable nymph (ny) of A. armillatus with thin fibrous capsule in the lung. (B) Three cross sections of one viable A. armillatus in the intestinal wall with very little cellular reaction. (C) Body wall of a well-preserved vital nymph (ny) of A. armillatus in the liver with exuvia (arrow), a thick fibrous capsule, and moderate infiltration of the adjacent liver tissue. (D) Dead and degenerated A. armillatus in a lymph node with a thick fibrous capsule. (E) Linguatula nodule with target-like appearance in human lung. In the center of the nodule, a dead degenerated nymph (ny) is visible. Due to the coiled shape of the nymph, two adjacent fibrous rings are discernable on this section. (F) Granulomatous scar with central amorphous mass in the lung. Remnants of the cuticle (arrow) of L. serrata are still left. Scale bars: (C) = 100 mm; all others = 500 µm. Hematoxylin and eosin (B); trichrome stain (all others).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2643528&req=5

pntd-0000320-g005: Different types of tissue reactions of human patients to vital, degenerated, and nearly absorbed pentastome nymphs.(A) Viable nymph (ny) of A. armillatus with thin fibrous capsule in the lung. (B) Three cross sections of one viable A. armillatus in the intestinal wall with very little cellular reaction. (C) Body wall of a well-preserved vital nymph (ny) of A. armillatus in the liver with exuvia (arrow), a thick fibrous capsule, and moderate infiltration of the adjacent liver tissue. (D) Dead and degenerated A. armillatus in a lymph node with a thick fibrous capsule. (E) Linguatula nodule with target-like appearance in human lung. In the center of the nodule, a dead degenerated nymph (ny) is visible. Due to the coiled shape of the nymph, two adjacent fibrous rings are discernable on this section. (F) Granulomatous scar with central amorphous mass in the lung. Remnants of the cuticle (arrow) of L. serrata are still left. Scale bars: (C) = 100 mm; all others = 500 µm. Hematoxylin and eosin (B); trichrome stain (all others).
Mentions: In human patients, three types of pentastomid lesions have been described histologically [8],[11],[21]. In the first type, a viable nymph (Figures 5A–5C) is found in a cyst with little or no adjacent cellular infiltration of the host tissue, since the living nymph excretes only small amounts of antigenic compounds. Surrounding the parasite, usually a thin layer of homogenous, refractile, eosinophilic material of the exuvia is seen (Figures 5C and 5D, [24]). A narrow zone of epitheloid cells may adjoin the fibrous capsule (Figure 5C), peripheral to which are macrophages and, rarely, a few giant cells and lymphocytes. Usually only few or no eosinophils are seen [21]. Based on the morphology of the nymph, pentastomiasis can be diagnosed etiopathologically [11], and usually the pentastome genus or family can be identified in lesions of this type.

Bottom Line: In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis.Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations.This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.

View Article: PubMed Central - PubMed

Affiliation: Institute of Hygiene and Microbiology, University of Würzburg, Würzburg, Germany. dtappe@hygiene.uni-wuerzburg.de

ABSTRACT
Visceral pentastomiasis in humans is caused by the larval stages (nymphs) of the arthropod-related tongue worms Linguatula serrata, Armillifer armillatus, A. moniliformis, A. grandis, and Porocephalus crotali. The majority of cases has been reported from Africa, Malaysia, and the Middle East, where visceral pentastomiasis may be an incidental finding in autopsies, and less often from China and Latin America. In Europe and North America, the disease is only rarely encountered in immigrants and long-term travelers, and the parasitic lesions may be confused with malignancies, leading to a delay in the correct diagnosis. Since clinical symptoms are variable and serological tests are not readily available, the diagnosis often relies on histopathological examinations. This laboratory symposium focuses on the diagnosis of this unusual parasitic disease and presents its risk factors and epidemiology.

Show MeSH
Related in: MedlinePlus