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Inflammatory, Hypersensitivity and Immune Lung Diseases, including Parasitic Diseases.
Published in Fred W Wright, Radiology of the Chest and Related Conditions, 2022
Filariasis - three forms are of medical importance - Loa-Loa, Wucheria bancrofti and Onchcercosis. Worms in this group produce microfilariae, which undergo maturation in an insect (often the mosquito, especially Culix fatigans) and are thence transferred to man. Loa-Loa worms are transferred by horse-flies and may produce small calcified nodules 'Calabar swellings' (named after a town in Nigeria). The filarial worms tend to lodge in regional lymph nodes and cause lymphatic obstruction by mechanical means when they are present in large numbers, and by inflammatory reaction when they die and disintegrate. The affected nodes enlarge and contain dilated sinusoids, the nodal obstruction causing dilatation of more peripheral lymph vessels and lymphoedema and 'elephantiasis'. A novel way of diagnosing the condition is to use scrotal ultrasound when dilated lymphatics (sometimes containing wriggling live worms) may be seen (Dreyer et al., 1994). Chylothoraces and thoracic duct obstruction are discussed on p. 14.10. Filariasis may also lead to endomyocardial fibrosis.
Infectious and parasitic causes of hypopigmentation
Published in Electra Nicolaidou, Clio Dessinioti, Andreas D. Katsambas, Hypopigmentation, 2019
Serena Gianfaldoni, Aleksandra Vojvodic, Nooshin Bagherani, Bruce R. Smoller, Balachandra Ankad, Leon Gilad, Arieh Ingber, Fabrizio Guarneri, Uwe Wollina, Torello Lotti
Ivermectin (microfilaricidal), administered once or, preferably, twice yearly for the lifespan of adult worms (10–15 years), or as long as evidence of skin or eye infection exists, is the treatment of choice.40,48 Adjustment of treatment strategy is required for patients with high blood levels of Loa loa, to avoid possibly severe adverse events.48 Because of bactericidal effects on Wolbachia, doxycyclin is indirectly lethal for adult Onchocerca volvulus, offering a new, promising therapeutic approach.49
Flies (Biting)
Published in Gail Miriam Moraru, Jerome Goddard, The Goddard Guide to Arthropods of Medical Importance, Seventh Edition, 2019
Gail Miriam Moraru, Jerome Goddard
Deer flies belong to the family Tabanidae (the same one as horse flies) but are usually much smaller. Deer flies are extremely annoying to people in the outdoors during summer months, often circling persistently around the head. Like horse flies, deer flies have scissorlike mouthparts and can inflict painful bites. Deer fly bites often become secondarily infected; in hypersensitive individuals, they have been known to produce systemic reactions characterized by generalized urticaria and wheezing. In the United States, the deer fly Chrysops discalis mechanically transmits tularemia organisms from rabbits to people by its bites, a condition sometimes referred to as deer fly fever.10–12 During one outbreak, 64% of human cases of tularemia in Wyoming were attributed to deer fly bites.13 In the African equatorial rainforest, deer flies (particularly C. silacea and C. dimidiata) transmit the filarial nematode parasite Loa loa (Figure 19.8). Loiasis affects an estimated 10 million individuals and is characterized by Calabar swellings (localized nonpitting edema mainly on the wrists or ankles, 5–20 cm in diameter, lasting from a few hours to a few days), generalized pruritus, arthralgia, fatigue, hypereosinophilia, and sometimes serious central nervous system (CNS) involvement.14,15 The pathognomonic symptom of loiasis, subconjunctival migration of the worm in the eye, is uncommon but still reported.16
Relationships between T-scores at the hip and bone mineral density at the distal femur and proximal tibia in persons with spinal cord injury
Published in The Journal of Spinal Cord Medicine, 2020
Christopher M. Cirnigliaro, J. Scott Parrott, Mary Jane Myslinski, Pierre Asselin, Alexander T. Lombard, Michael F. La Fountaine, Steven C. Kirshblum, Gail F. Forrest, Trevor Dyson-Hudson, Ann M. Spungen, William A. Bauman
The Bland–Altman analysis was used to examine agreement between predicted and measured values based on the linear regression equations obtained. A small mean difference (bias) between the predicted and measured values was observed for all regions (<0.1 SD). Analysis of the 95% CI limit of agreement (LOA) using the DF and PT to predict T-scores ranged from −1.991 to 1.990 and −1.938 to 1.939 at the TH, respectively, (Fig. 2 A and B, light dashed lines) and −1.825 to 1.827 and −1.770 to 1.770 at the FN, respectively (Fig. 2 C and D, light dashed lines). For TH and FN regions, the regression estimates from the DF and PT predicted between 93 and 94% of the total sample of T-scores (Fig. 2 A-D). A second clinically relevant LOA (LOAclin) was set at the acceptable threshold (±1 SD) with the DF and PT accurately predicting 75% and 71% of TH T-score values, respectively, and 76% of FN T-score values, respectively (Fig. 2 A-D). Despite the overall good levels of agreement between the difference and measured values, when the predicted and observed T-score values are outside the 95% limit of agreement, the predicted T-score values are lower than the measured T-score values, overestimating the measured values between −2.0 and −4.0 SD, evidence that measures at the hip and knee region should be obtained separately in populations with a high prevalence of osteoporosis that are at increased risk for fracture.
An unexpected peripheral blood finding: microfilaria
Published in Baylor University Medical Center Proceedings, 2020
John R. Krause, Meleissa Hutcheson, Rebecca Ardoin
The roundworm in our patient was Mansonella perstans, one of the three filarial species in the genus Mansonella (the other two being M. ozzardi and M. streptocerca), which are included in the category of serous cavity filariasis. In mammalian hosts, adult Mansonella worms are located in connective tissues or peritoneal, pleural, or pericardial cavities.4 Microfilaria of M. perstans will circulate in the blood and are approximately 190 to 200 μm in length × 4 μm (slightly smaller than the diameter of a red blood cell). The microfilariae are unsheathed; the tail tapers to a bluntly rounded end and nuclei extend to the end of the tail.5 Because the microfilariae are small, they can be overlooked in blood films. In the blood, they may be distinguished from other sympatric microfilariae including Loa loa or Wuchereria bancrofti, which are longer and sheathed and have larger terminal nuclei.5
Moxidectin: an oral treatment for human onchocerciasis
Published in Expert Review of Anti-infective Therapy, 2020
Philip Milton, Jonathan I. D. Hamley, Martin Walker, María-Gloria Basáñez
A major limitation to the implementation of ivermectin MDA in communities that are hypoendemic for onchocerciasis but co-endemic with loiasis (another filarial infection, caused by Loa loa, and distributed in the forest belt of central Africa) is the risk of SAEs (e.g. encephalitis, coma, death), following microfilaricidal treatment of individuals with heavy L. loa microfilaremia [72]. Although Gardon et al. [72] found a significantly increased risk of developing prolonged functional impairment above 8,000 L. loa microfilariae/mL of blood, and an increased risk of encephalopathy above 30,000 microfilariae/mL, others have used ≥20,000 as the SAE threshold [88]. Hypoendemic onchocerciasis–loiasis co-endemic areas with L. loa prevalence >20% (where it is expected that 2–9% of individuals harbor ≥30,000 microfilariae/mL) would be excluded from CDTI [13]. In these situations, test-and-not-treat (TNT) protocols have been successfully piloted [88] which test for L. loa microfilaremia levels in community residents, and for those harboring levels above those associated with SAEs, albendazole (or anti-Wolbachia therapies, see 4.2. Other compounds in clinical development), but not ivermectin, may be offered. Although clinical trials have yet to be conducted to assess the safety of moxidectin in onchocerciasis–loiasis co-endemic areas, it could potentially be used in TNT modalities of drug distribution, after having established safe (L. loa) microfilaremia thresholds for treatment. Once a safe microfilaremia threshold is established, it would also be important to determine the efficacy of moxidectin for treating (low to moderate) L. loa infection (see [89] for a meta-analysis of studies investigating the effect of ivermectin on L. loa), and to determine the need to re-test individuals for levels of loiasis microfilaremia following initiation of TNT with moxidectin.