- Email: [email protected]
Severe pneumonia during primary infection with an atypical strain of Toxoplasma gondii in an immunocompetent young man
Journal of Infection (2006) 53, e47ee50
www.elsevierhealth.com/journals/jinf
CASE REPORT
Severe pneumonia during primary infection with an atypical strain of Toxoplasma gondii in an immunocompetent young man ¨t a,*, Daniel Ajzenberg b, Francine De Salvador-Guilloue Sylvie Chaillou-Opitz a, Marie-Christine Saint-Paul c, Brigitte Dunais a, Pierre Dellamonica a, Pierre Marty d a
Centre Hospitalier-Universitaire de Nice, Service d’Infectiologie, Hoˆpital de l’Archet, BP 3079 06202 e Nice Cedex 3, France b Universite´ de Limoges, Faculte´ de Me´decine, EA3174, Laboratoire de Parasitologie-Mycologie, 87031 e Limoges Cedex, France c Centre Hospitalier-Universitaire de Nice, Laboratoire d’Anatomie Pathologique, Hoˆpital Pasteur, 06300 e Nice, France d Centre Hospitalier-Universitaire de Nice, Laboratoire de Parasitologie-Mycologie, Hoˆpital de l’Archet, BP 3079 06202 e Nice Cedex 3, France Accepted 28 October 2005 Available online 15 December 2005
KEYWORDS Severe toxoplasmosis; Toxoplasma; Pneumonia; Immunocompetent; Atypical strain
Summary We report a case of severe acute primary pulmonary toxoplasmosis in an immunocompetent young man living in Nice (Southern France). The Toxoplasma DNA extracted from the broncho-alveolar lavage fluid allowed a genetic characterization of the responsible strain which displayed an atypical genotype of Toxoplasma gondii. This unusual genetic composition of the parasite may have influenced, among other factors, the severity of the disease. ª 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction
* Corresponding author. Tel.: þ33 4 92 03 54 67; fax: þ33 4 92 03 54 69. E-mail address: [email protected] (F. De SalvadorGuilloue ¨t).
Toxoplasma gondii is an obligate intracellular apicomplexan with a worldwide distribution. This parasite can infect virtually all warm-blooded animals and uses felids as the definitive host. In humans, prevalence is high ranging between 15 and 85% of the world adult human population depending on
0163-4453/$30 ª 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2005.10.026
e48 geographical location.1 When acquired congenitally2 or as a consequence of reactivation in immunocompromised patients,3 toxoplasmosis can be lifethreatening. Conversely, in immunocompetent children and adults, human acquired toxoplasmosis is either usually asymptomatic, or associated in 10% of cases to cervical or occipital lymphadenopathy.4 However, much less frequently, severe acquired forms in immunocompetent individuals are also described such as chorioretinitis5 or pulmonary forms.6,7 A correlation between atypical genotypes of T. gondii and this unusual clinical outcome in immunocompetent patients has been reported.7,8 We report a case of pneumonia caused by an atypical strain of T. gondii in an immunocompetent young man.
Case report A 19-year-old male living in the Nice area (Southern France), with no past medical history, presented with fever, fatigue and dyspnoea of 15 days’ duration. Upon clinical examination, the patient had a body temperature of 39.5 C, myalgia, dry cough, dyspnoea, cervical, axillary and inguinal lymphadenopathy, with liver and spleen enlargement. The chest X-ray showed interstitial infiltrates involving both lungs. The partial pressure of oxygen in arterial blood was 62 mmHg. The patient’s white cell count was 9.6 109/l with 31.6% granulocytes, 60.8% lymphocytes among which hyperbasophilic lymphocytes, 7% (406/mm3) CD4þ T-cells, and 59% CD8þT-cells. Other laboratory values were as follows: aspartate aminotransferase (AST) 65 U/l (1.5 N), alanine aminotransferase (ALT) 115 U/l (2 N), and Creactive protein 42 mg/l. Repeated serological testing for HIV, EBV and CMV remained negative. The patient underwent bronchoscopy with broncho-alveolar lavage (BAL). The total cell count in the BAL fluid was 450/mm3 with 44% macrophages, 55% lymphocytes and 1% granulocytes. No bacteria, fungi or acid-fast bacilli could be detected but rare tachyzoites of T. gondii were identified. The serological tests for toxoplasmosis were positive. Table 1 summarizes the serological data at days 0, 7, 21 and 78. The patient was treated with a pyrimethaminee sulfadiazine combination. The outcome was favourable with resolution of fever, fatigue and dyspnoea; the C-reactive protein decreased to 3 mg/l, and liver function tests returned to normal and CD4 cells increased to normal value. Two months later serological testing showed a major increase in antiToxoplasma IgG levels with a drop in IgM index and an increase of IgG avidity and IgA index.
F. De Salvador-Guilloue ¨t et al. Table 1
Serological data
IgG (UMEIA/ml)a IgM (index)b IgA (index)b Avidity index a b
Cut-off value
Day 0
Day 7
Day 21
Day 78
3
35
85
94
2325
0.6
8.50
8.40 8.06 1.68
0.7
0.96
1.04 0.71 4.96
ND, IgG 0.17 0.26 0.65 >0.3, Toxo > 3 too low months
AxSYM Abbott Diagnostic. Elisa SFRI Diagnostic.
Toxoplasma DNA, called LPN-2003-FOU, has been extracted directly from the BAL fluid for a genetic characterization. LPN-2003-FOU has been sequenced at five polymorphic microsatellite markers (TUB2, W35, TgM-A, B18 and B17). Reaction mixtures and amplification conditions were according to published method.9 All sequences were submitted to GenBank (accession numbers: DQ218329eDQ218333). These sequences were aligned with sequences from archetypal type I, II and III strains (Fig. 1). LPN-2003-FOU exhibits an atypical genotype shuffling one typical allele at B18 (i.e. identical to the corresponding allele of type I or III strains) with four atypical alleles at TUB2, W35, TgM-A and B17 (i.e. different from corresponding alleles of type I, II or III). The atypical alleles consisted of unique nucleotide polymorphisms in microsatellite flanking regions (at W35, TgM-A and B17) or unusual numbers of dinucleotide repeats in microsatellite regions ((CA)6 at TUB2 and (TC)16 at B17).
Discussion Our patient had severe clinical expression of primary toxoplasmosis which presented as dyspnoeic pneumonia. If the lung represents a relatively common site of T. gondii disease in persons with AIDS,4 Toxoplasma pneumonia is exceptional in immunocompetent patients: in reviewing the past 50 years literature (from 1941 to 1991), Pomeroy and Filice6 identified only 15 patients with Toxoplasma pneumonia and no identifiable defect in host defence. Since then, such cases were occasionally described in literature.10 However, this unusual clinical presentation could be more frequent in tropical areas: in French Guiana, 19 welldocumented cases of severe acute disseminated
TUB2
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184
Severe toxoplasmosis in an immunocompetent patient
C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A * *
LPN-2003-FOU
C A C A C A C A C A C A * * * *
C T G T C T C T CT CT CT C T CT C T C T C T G T G * * G C CG G T C T C T CT CT CT C T C * * * * * * T G T G * * A T
NED (III) LPN-2003-FOU
CG A T C T C T CT CT CT C * * * * * * * * T G T G T GG T T G G T C T C T CT CT CT C T C * * * * * * T G T G * * G T
TgM-A BK (I)
A C T G T G T G T G T G T G T G T G T G
ME49 (II)
A C T G T G T G T G T G T G T G T G * *
NED (III)
A T T G T G T G T G T G T G T G * * * *
LPN-2003-FOU
A C T G T G T G T G T G T G T G T G * * G
B18
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
BK (I) ME49 (II)
16 30 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
W35
35 36 38 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 105 142
BK (I) ME49 (II), NED (III)
C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A * *
BK (I)
33 34 54 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127
BK (I), NED (III), LPN-2003-FOU ME49 (II)
B17
e49
T GC T C T C T C T C T C T C T C T C T C T C * * * * * * * * * * * *
ME49 (II), NED (III)
G A C T C T C T C T C T C T C T C * * * * * * * * * * * * * * * * * *
LPN-2003-FOU
G A T T C T C T C T C T C T C T C T C T C T C T C T C T C T C T C T C
Figure 1 Nucleotide polymorphisms at five microsatellite markers (TUB2, W35, TgM-A, B18 and B17). Sequences from archetypal type I (BK), type II (ME49) and type III (NED) strains were compared with sequences obtained from the LPN-2003-FOU DNA. Boxes with black background indicate unique nucleotide polymorphisms not shared by at least two archetypal sequences; ()) indicates deletion sites. Nucleotide sequence data are available on GenBank under the accession numbers: AY572593 (BK, TUB2), AY572621 (BK, W35), AY572650 (BK, TGM-A), AY572714 (BK, B18), AY572751 (BK, B17), AY572581 (ME49, TUB2), AY572631 (ME49, W35), AY572661 (ME49, TGM-A), AY572710 (ME49, B18), AY572759 (ME49, B17), AY572595 (NED, TUB2), AY572632 (NED, W35), AY572662 (NED, TGM-A), AY572726 (NED, B18), AY572760 (NED, B17), DQ218329eDQ218333 (LPN-2003-FOU).
toxoplasmosis acquired by immunocompetent adults have been reported between 1995 and 2002.7,11e13 The clinical presentations consisted of a marked, non-specific infectious syndrome accompanied by an altered general status with at least one visceral localization. Pulmonary involvement was the most frequent with respiratory distress complication in about one case out of three.7 In these severe forms of toxoplasmosis, humans are accidental hosts of the wild cycle of T. gondii in the Amazonian rainforest. Among the factors influencing the severity of primary infection with T. gondii, the genotype of the responsible strain may play a major role.14 If the identification of clearly defined genes involved in pathogenesis is still lacking in Toxoplasma, several clues brought by genotyping analyses plead for a role of the genetic composition of the parasite in the outcome of the disease. In the domestic cycle
of Toxoplasma in Europe or USA, between cats, humans, peri-domestic and domestic animals such as pigs and sheep, the vast majority (>95%) of T. gondii strains can be grouped into one of three distinct clonal lineages called type I, II and III.15 Several studies in France have reported that type II strains dominate in AIDS and congenital infection.16,17 Strains with an atypical genotype (i.e. not related to the three main lineages with many unique polymorphisms at many markers) are exceptionally isolated in Europe or USA but might be more common outside of these areas. For instance, all French Guianan isolates described in literature9 have unique and atypical genotypes. In human disease, these atypical strains are associated with uncommon and/or severe forms of toxoplasmosis: ocular forms in the USA,8 severe congenital toxoplasmosis in France,17 pneumonia in immunocompetent patients in French Guiana7
e50 and recently atypical recurrence in an HIV-infected patient.18 Because these atypical strains are drawing on genes that are outside the domestic gene pool that contributes to types I, II and III, the severity of infection in humans could be explained, in part, by a poor adaptation of immune system against these atypical genotypes. The genotype of the strain associated with the pulmonary form described in this study is clearly atypical with unique polymorphisms at four microsatellite markers over the five tested. This indicates a potential source of atypical strains not only in exotic regions like French Guiana, but also in France, even if the number of reported cases remains very low. This was the case, some years ago, in this area of Nice in France, where an atypical isolate was responsible for disseminated toxoplasmosis in a foetus and atypical maternal toxoplasmosis.17 Other factors such as the parasite life-cycle stage (oocysts versus cysts), inoculum size and genetic heterogeneity of the host are known to influence the severity of the disease.14 At the same time, the sister of the patient presented in this case report, 11 years old, exhibited fever and cervical lymphadenopathy without pulmonary symptoms. An acute toxoplasmosis was diagnosed on serological tests (IgG 61 UMEIA, low IgG avidity, presence of IgM and IgA antibodies). Her state improved spontaneously. This observation suggests a common source of contamination (the brother and the sister had close contacts with a kitten) and thus clearly indicates that the parasite genotype is not responsible alone for the severe outcome of the disease in our case report. A massive parasite inoculum only in the brother may have overwhelmed the immune response and led to a severe form of toxoplasmosis. In such grouped cases, differences in inoculum size are more likely explained by ingestion of oocysts rather than ingestion of cysts in infected meat.
Conclusion T. gondii primary infection in immunocompetent children and adults is usually asymptomatic or benign. However, in rare cases, a severe outcome such as pneumonia can be seen. In these cases, different factors such as parasite genotype, parasite life-cycle stage (oocysts versus cysts), inoculum size and genetic heterogeneity of the host are combined together to explain the severity of disease.
F. De Salvador-Guilloue ¨t et al.
Acknowledgements We thank Marie-Laure Darde ´ for critically reading the manuscript.
References 1. Dubey JP, Beattie CP. Toxoplasmosis of animals and man. Boca Raton, FL: CRC Press, Inc.; 1988. 2. Wong SY, Remington JS. Toxoplasmosis in pregnancy. Clin Infect Dis 1994;18:853e62. 3. Luft BJ, Remington JS. Toxoplasmic encephalitis in AIDS. Clin Infect Dis 1992;15:211e22. 4. Montoya JG, Liesenfeld O. Toxoplasmosis. Lancet 2004;363: 1965e76. 5. Burnett AJ, Shortt SG, Isaac-Renton J, King A, Werker D, Bowie WR. Multiple cases of acquired toxoplasmosis retinitis presenting in an outbreak. Ophthalmology 1998;105: 1032e7. 6. Pomeroy C, Filice GA. Pulmonary toxoplasmosis: a review. Clin Infect Dis 1992;14:863e70. 7. Carme B, Bissuel F, Ajzenberg D, Bouyne R, Aznar C, Demar M, et al. Severe acquired toxoplasmosis in immunocompetent adult patients in French Guiana. J Clin Microbiol 2002;40:4037e44. 8. Grigg ME, Ganatra J, Boothroyd JC, Margolis TP. Unusual abundance of atypical strains associated with human ocular toxoplasmosis. J Infect Dis 2001;184:633e9. 9. Ajzenberg D, Ban ˜uls AL, Su C, Dume `tre A, Demar M, Carme B, et al. Genetic diversity, clonality and sexuality in Toxoplasma gondii. Int J Parasitol 2004;34:1185e96. 10. Candolfi E, de Blay F, Rey D, Christmann D, Treisser A, Pauli G, et al. A parasitologically proven case of Toxoplasma pneumonia in an immunocompetent pregnant women. J Infect 1993;26:79e81. 11. Bossi P, Caumes E, Paris L, Darde ´ ML, Bricaire F. Toxoplasma gondii-associated GuillaineBarre ´ syndrome in an immunocompetent patient. J Clin Microbiol 1998;36:3724e5. 12. Darde ´ ML, Villena I, Pinon JM, Beguinot I. Severe toxoplasmosis caused by a Toxoplasma gondii strain with a new isoenzyme type acquired in French Guiana. J Clin Microbiol 1998;36:324. 13. Bossi P, Bricaire F. Severe acute disseminated toxoplasmosis. Lancet 2004;364:579. 14. Sibley LD, Howe DK. Genetic basis of pathogenicity in toxoplasmosis. Curr Top Microbiol Immunol 1996;219:3e15. 15. Howe DK, Sibley LD. Toxoplasma gondii comprises three clonal lineages: correlation of parasite genotype with human disease. J Infect Dis 1995;172:1561e6. 16. Honore ´ S, Couvelard A, Garin YJF, Bedel C, He ´nin D, Darde ´ ML, et al. Ge ´notypage de souches de Toxoplasma gondii chez des patients immunode ´prime ´s. Pathol Biol 2000;48:541e7. 17. Ajzenberg D, Cogne ´ N, Paris L, Bessie `res MH, Thulliez P, Filisetti D, et al. Genotype of 86 Toxoplasma gondii isolates associated with human congenital toxoplasmosis, and correlation with clinical findings. J Infect Dis 2002;186:684e9. 18. Ghosn J, Paris L, Ajzenberg D, Carcelain G, Darde ´ ML, Tubiana R, et al. Atypical toxoplasmic manifestation after discontinuation of maintenance therapy in a human immunodeficiency virus type 1-infected patient with immune recovery. Clin Infect Dis 2003;37:e112e4.
www.elsevierhealth.com/journals/jinf
CASE REPORT
Severe pneumonia during primary infection with an atypical strain of Toxoplasma gondii in an immunocompetent young man ¨t a,*, Daniel Ajzenberg b, Francine De Salvador-Guilloue Sylvie Chaillou-Opitz a, Marie-Christine Saint-Paul c, Brigitte Dunais a, Pierre Dellamonica a, Pierre Marty d a
Centre Hospitalier-Universitaire de Nice, Service d’Infectiologie, Hoˆpital de l’Archet, BP 3079 06202 e Nice Cedex 3, France b Universite´ de Limoges, Faculte´ de Me´decine, EA3174, Laboratoire de Parasitologie-Mycologie, 87031 e Limoges Cedex, France c Centre Hospitalier-Universitaire de Nice, Laboratoire d’Anatomie Pathologique, Hoˆpital Pasteur, 06300 e Nice, France d Centre Hospitalier-Universitaire de Nice, Laboratoire de Parasitologie-Mycologie, Hoˆpital de l’Archet, BP 3079 06202 e Nice Cedex 3, France Accepted 28 October 2005 Available online 15 December 2005
KEYWORDS Severe toxoplasmosis; Toxoplasma; Pneumonia; Immunocompetent; Atypical strain
Summary We report a case of severe acute primary pulmonary toxoplasmosis in an immunocompetent young man living in Nice (Southern France). The Toxoplasma DNA extracted from the broncho-alveolar lavage fluid allowed a genetic characterization of the responsible strain which displayed an atypical genotype of Toxoplasma gondii. This unusual genetic composition of the parasite may have influenced, among other factors, the severity of the disease. ª 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.
Introduction
* Corresponding author. Tel.: þ33 4 92 03 54 67; fax: þ33 4 92 03 54 69. E-mail address: [email protected] (F. De SalvadorGuilloue ¨t).
Toxoplasma gondii is an obligate intracellular apicomplexan with a worldwide distribution. This parasite can infect virtually all warm-blooded animals and uses felids as the definitive host. In humans, prevalence is high ranging between 15 and 85% of the world adult human population depending on
0163-4453/$30 ª 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.jinf.2005.10.026
e48 geographical location.1 When acquired congenitally2 or as a consequence of reactivation in immunocompromised patients,3 toxoplasmosis can be lifethreatening. Conversely, in immunocompetent children and adults, human acquired toxoplasmosis is either usually asymptomatic, or associated in 10% of cases to cervical or occipital lymphadenopathy.4 However, much less frequently, severe acquired forms in immunocompetent individuals are also described such as chorioretinitis5 or pulmonary forms.6,7 A correlation between atypical genotypes of T. gondii and this unusual clinical outcome in immunocompetent patients has been reported.7,8 We report a case of pneumonia caused by an atypical strain of T. gondii in an immunocompetent young man.
Case report A 19-year-old male living in the Nice area (Southern France), with no past medical history, presented with fever, fatigue and dyspnoea of 15 days’ duration. Upon clinical examination, the patient had a body temperature of 39.5 C, myalgia, dry cough, dyspnoea, cervical, axillary and inguinal lymphadenopathy, with liver and spleen enlargement. The chest X-ray showed interstitial infiltrates involving both lungs. The partial pressure of oxygen in arterial blood was 62 mmHg. The patient’s white cell count was 9.6 109/l with 31.6% granulocytes, 60.8% lymphocytes among which hyperbasophilic lymphocytes, 7% (406/mm3) CD4þ T-cells, and 59% CD8þT-cells. Other laboratory values were as follows: aspartate aminotransferase (AST) 65 U/l (1.5 N), alanine aminotransferase (ALT) 115 U/l (2 N), and Creactive protein 42 mg/l. Repeated serological testing for HIV, EBV and CMV remained negative. The patient underwent bronchoscopy with broncho-alveolar lavage (BAL). The total cell count in the BAL fluid was 450/mm3 with 44% macrophages, 55% lymphocytes and 1% granulocytes. No bacteria, fungi or acid-fast bacilli could be detected but rare tachyzoites of T. gondii were identified. The serological tests for toxoplasmosis were positive. Table 1 summarizes the serological data at days 0, 7, 21 and 78. The patient was treated with a pyrimethaminee sulfadiazine combination. The outcome was favourable with resolution of fever, fatigue and dyspnoea; the C-reactive protein decreased to 3 mg/l, and liver function tests returned to normal and CD4 cells increased to normal value. Two months later serological testing showed a major increase in antiToxoplasma IgG levels with a drop in IgM index and an increase of IgG avidity and IgA index.
F. De Salvador-Guilloue ¨t et al. Table 1
Serological data
IgG (UMEIA/ml)a IgM (index)b IgA (index)b Avidity index a b
Cut-off value
Day 0
Day 7
Day 21
Day 78
3
35
85
94
2325
0.6
8.50
8.40 8.06 1.68
0.7
0.96
1.04 0.71 4.96
ND, IgG 0.17 0.26 0.65 >0.3, Toxo > 3 too low months
AxSYM Abbott Diagnostic. Elisa SFRI Diagnostic.
Toxoplasma DNA, called LPN-2003-FOU, has been extracted directly from the BAL fluid for a genetic characterization. LPN-2003-FOU has been sequenced at five polymorphic microsatellite markers (TUB2, W35, TgM-A, B18 and B17). Reaction mixtures and amplification conditions were according to published method.9 All sequences were submitted to GenBank (accession numbers: DQ218329eDQ218333). These sequences were aligned with sequences from archetypal type I, II and III strains (Fig. 1). LPN-2003-FOU exhibits an atypical genotype shuffling one typical allele at B18 (i.e. identical to the corresponding allele of type I or III strains) with four atypical alleles at TUB2, W35, TgM-A and B17 (i.e. different from corresponding alleles of type I, II or III). The atypical alleles consisted of unique nucleotide polymorphisms in microsatellite flanking regions (at W35, TgM-A and B17) or unusual numbers of dinucleotide repeats in microsatellite regions ((CA)6 at TUB2 and (TC)16 at B17).
Discussion Our patient had severe clinical expression of primary toxoplasmosis which presented as dyspnoeic pneumonia. If the lung represents a relatively common site of T. gondii disease in persons with AIDS,4 Toxoplasma pneumonia is exceptional in immunocompetent patients: in reviewing the past 50 years literature (from 1941 to 1991), Pomeroy and Filice6 identified only 15 patients with Toxoplasma pneumonia and no identifiable defect in host defence. Since then, such cases were occasionally described in literature.10 However, this unusual clinical presentation could be more frequent in tropical areas: in French Guiana, 19 welldocumented cases of severe acute disseminated
TUB2
169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184
Severe toxoplasmosis in an immunocompetent patient
C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A * *
LPN-2003-FOU
C A C A C A C A C A C A * * * *
C T G T C T C T CT CT CT C T CT C T C T C T G T G * * G C CG G T C T C T CT CT CT C T C * * * * * * T G T G * * A T
NED (III) LPN-2003-FOU
CG A T C T C T CT CT CT C * * * * * * * * T G T G T GG T T G G T C T C T CT CT CT C T C * * * * * * T G T G * * G T
TgM-A BK (I)
A C T G T G T G T G T G T G T G T G T G
ME49 (II)
A C T G T G T G T G T G T G T G T G * *
NED (III)
A T T G T G T G T G T G T G T G * * * *
LPN-2003-FOU
A C T G T G T G T G T G T G T G T G * * G
B18
33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52
BK (I) ME49 (II)
16 30 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66
W35
35 36 38 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 105 142
BK (I) ME49 (II), NED (III)
C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A C A * *
BK (I)
33 34 54 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127
BK (I), NED (III), LPN-2003-FOU ME49 (II)
B17
e49
T GC T C T C T C T C T C T C T C T C T C T C * * * * * * * * * * * *
ME49 (II), NED (III)
G A C T C T C T C T C T C T C T C * * * * * * * * * * * * * * * * * *
LPN-2003-FOU
G A T T C T C T C T C T C T C T C T C T C T C T C T C T C T C T C T C
Figure 1 Nucleotide polymorphisms at five microsatellite markers (TUB2, W35, TgM-A, B18 and B17). Sequences from archetypal type I (BK), type II (ME49) and type III (NED) strains were compared with sequences obtained from the LPN-2003-FOU DNA. Boxes with black background indicate unique nucleotide polymorphisms not shared by at least two archetypal sequences; ()) indicates deletion sites. Nucleotide sequence data are available on GenBank under the accession numbers: AY572593 (BK, TUB2), AY572621 (BK, W35), AY572650 (BK, TGM-A), AY572714 (BK, B18), AY572751 (BK, B17), AY572581 (ME49, TUB2), AY572631 (ME49, W35), AY572661 (ME49, TGM-A), AY572710 (ME49, B18), AY572759 (ME49, B17), AY572595 (NED, TUB2), AY572632 (NED, W35), AY572662 (NED, TGM-A), AY572726 (NED, B18), AY572760 (NED, B17), DQ218329eDQ218333 (LPN-2003-FOU).
toxoplasmosis acquired by immunocompetent adults have been reported between 1995 and 2002.7,11e13 The clinical presentations consisted of a marked, non-specific infectious syndrome accompanied by an altered general status with at least one visceral localization. Pulmonary involvement was the most frequent with respiratory distress complication in about one case out of three.7 In these severe forms of toxoplasmosis, humans are accidental hosts of the wild cycle of T. gondii in the Amazonian rainforest. Among the factors influencing the severity of primary infection with T. gondii, the genotype of the responsible strain may play a major role.14 If the identification of clearly defined genes involved in pathogenesis is still lacking in Toxoplasma, several clues brought by genotyping analyses plead for a role of the genetic composition of the parasite in the outcome of the disease. In the domestic cycle
of Toxoplasma in Europe or USA, between cats, humans, peri-domestic and domestic animals such as pigs and sheep, the vast majority (>95%) of T. gondii strains can be grouped into one of three distinct clonal lineages called type I, II and III.15 Several studies in France have reported that type II strains dominate in AIDS and congenital infection.16,17 Strains with an atypical genotype (i.e. not related to the three main lineages with many unique polymorphisms at many markers) are exceptionally isolated in Europe or USA but might be more common outside of these areas. For instance, all French Guianan isolates described in literature9 have unique and atypical genotypes. In human disease, these atypical strains are associated with uncommon and/or severe forms of toxoplasmosis: ocular forms in the USA,8 severe congenital toxoplasmosis in France,17 pneumonia in immunocompetent patients in French Guiana7
e50 and recently atypical recurrence in an HIV-infected patient.18 Because these atypical strains are drawing on genes that are outside the domestic gene pool that contributes to types I, II and III, the severity of infection in humans could be explained, in part, by a poor adaptation of immune system against these atypical genotypes. The genotype of the strain associated with the pulmonary form described in this study is clearly atypical with unique polymorphisms at four microsatellite markers over the five tested. This indicates a potential source of atypical strains not only in exotic regions like French Guiana, but also in France, even if the number of reported cases remains very low. This was the case, some years ago, in this area of Nice in France, where an atypical isolate was responsible for disseminated toxoplasmosis in a foetus and atypical maternal toxoplasmosis.17 Other factors such as the parasite life-cycle stage (oocysts versus cysts), inoculum size and genetic heterogeneity of the host are known to influence the severity of the disease.14 At the same time, the sister of the patient presented in this case report, 11 years old, exhibited fever and cervical lymphadenopathy without pulmonary symptoms. An acute toxoplasmosis was diagnosed on serological tests (IgG 61 UMEIA, low IgG avidity, presence of IgM and IgA antibodies). Her state improved spontaneously. This observation suggests a common source of contamination (the brother and the sister had close contacts with a kitten) and thus clearly indicates that the parasite genotype is not responsible alone for the severe outcome of the disease in our case report. A massive parasite inoculum only in the brother may have overwhelmed the immune response and led to a severe form of toxoplasmosis. In such grouped cases, differences in inoculum size are more likely explained by ingestion of oocysts rather than ingestion of cysts in infected meat.
Conclusion T. gondii primary infection in immunocompetent children and adults is usually asymptomatic or benign. However, in rare cases, a severe outcome such as pneumonia can be seen. In these cases, different factors such as parasite genotype, parasite life-cycle stage (oocysts versus cysts), inoculum size and genetic heterogeneity of the host are combined together to explain the severity of disease.
F. De Salvador-Guilloue ¨t et al.
Acknowledgements We thank Marie-Laure Darde ´ for critically reading the manuscript.
References 1. Dubey JP, Beattie CP. Toxoplasmosis of animals and man. Boca Raton, FL: CRC Press, Inc.; 1988. 2. Wong SY, Remington JS. Toxoplasmosis in pregnancy. Clin Infect Dis 1994;18:853e62. 3. Luft BJ, Remington JS. Toxoplasmic encephalitis in AIDS. Clin Infect Dis 1992;15:211e22. 4. Montoya JG, Liesenfeld O. Toxoplasmosis. Lancet 2004;363: 1965e76. 5. Burnett AJ, Shortt SG, Isaac-Renton J, King A, Werker D, Bowie WR. Multiple cases of acquired toxoplasmosis retinitis presenting in an outbreak. Ophthalmology 1998;105: 1032e7. 6. Pomeroy C, Filice GA. Pulmonary toxoplasmosis: a review. Clin Infect Dis 1992;14:863e70. 7. Carme B, Bissuel F, Ajzenberg D, Bouyne R, Aznar C, Demar M, et al. Severe acquired toxoplasmosis in immunocompetent adult patients in French Guiana. J Clin Microbiol 2002;40:4037e44. 8. Grigg ME, Ganatra J, Boothroyd JC, Margolis TP. Unusual abundance of atypical strains associated with human ocular toxoplasmosis. J Infect Dis 2001;184:633e9. 9. Ajzenberg D, Ban ˜uls AL, Su C, Dume `tre A, Demar M, Carme B, et al. Genetic diversity, clonality and sexuality in Toxoplasma gondii. Int J Parasitol 2004;34:1185e96. 10. Candolfi E, de Blay F, Rey D, Christmann D, Treisser A, Pauli G, et al. A parasitologically proven case of Toxoplasma pneumonia in an immunocompetent pregnant women. J Infect 1993;26:79e81. 11. Bossi P, Caumes E, Paris L, Darde ´ ML, Bricaire F. Toxoplasma gondii-associated GuillaineBarre ´ syndrome in an immunocompetent patient. J Clin Microbiol 1998;36:3724e5. 12. Darde ´ ML, Villena I, Pinon JM, Beguinot I. Severe toxoplasmosis caused by a Toxoplasma gondii strain with a new isoenzyme type acquired in French Guiana. J Clin Microbiol 1998;36:324. 13. Bossi P, Bricaire F. Severe acute disseminated toxoplasmosis. Lancet 2004;364:579. 14. Sibley LD, Howe DK. Genetic basis of pathogenicity in toxoplasmosis. Curr Top Microbiol Immunol 1996;219:3e15. 15. Howe DK, Sibley LD. Toxoplasma gondii comprises three clonal lineages: correlation of parasite genotype with human disease. J Infect Dis 1995;172:1561e6. 16. Honore ´ S, Couvelard A, Garin YJF, Bedel C, He ´nin D, Darde ´ ML, et al. Ge ´notypage de souches de Toxoplasma gondii chez des patients immunode ´prime ´s. Pathol Biol 2000;48:541e7. 17. Ajzenberg D, Cogne ´ N, Paris L, Bessie `res MH, Thulliez P, Filisetti D, et al. Genotype of 86 Toxoplasma gondii isolates associated with human congenital toxoplasmosis, and correlation with clinical findings. J Infect Dis 2002;186:684e9. 18. Ghosn J, Paris L, Ajzenberg D, Carcelain G, Darde ´ ML, Tubiana R, et al. Atypical toxoplasmic manifestation after discontinuation of maintenance therapy in a human immunodeficiency virus type 1-infected patient with immune recovery. Clin Infect Dis 2003;37:e112e4.