Renal disease in chronic experimental Trypanosoma gambiense infections

Two recently isolated stocks of Trypanosoma brucei gambiense of human origin gave rise to a moderate to severe proliferative or membranoproliferative glomerulonephritis in 40 or 44 NMRI and C57BL/6J mice infected for 7-22 weeks. Extensive granular deposits of C3, IgG1 and IgG3 were found in the mesangium, together with smaller quantities of IgG2a, IgG2b, and IgM. No trypanosomal antigen could be detected in the deposits though specific anti-trypanosoma antibodies were found in kidney eluates. By electron microscopy, a conspicuous proliferation of mesangial and endothelial cells was observed and electron-dense deposits were seen in a mesangial and subepithelial localization. With one of these trypanosome stocks, four of seven Wistar rats infected for 9-15 weeks developed morphologically similar glomerular lesions. Four other trypanosome stocks did not evoke renal alterations in 17 other rats infected for 13-56 weeks. Experimental infection in mice or rats appears to be a suitable model for the study of renal disease in chronic African sleeping sickness.

Immune depression and macroglobulinemia in experimental subchronic trypanosomiasis

The effects of subchronic trypanosomiasis upon immune responses were examined in Trypanosoma gambiense infection and in subcurative treatment of T. brucei- and T- equiperdum-infected mice. About 60% of the mice infected with T. gambiense developed a subchronic infection similar to human trypanosomiasis, characterized by the absence of circulating trypanosomes. The animals died between 1 and 12 months after infection with elevated serum immunoglobulin M (IgM) levels (16 times the normal level). After 1 month of infection, the mice showed a normal primary antibody response against sheep erythrocytes, as tested by hemagglutination, despite their high serum IgM levels. After more than 1 month of infection, about 20% of the mice showed depressed hemagglutination titers (25% of control), whereas all relapsed mice that contained circulating parasites showed a pronounced suppression. Elimination of the blood parasites with Berenil treatment restored immune competence, which persisted until the relapse of the animals. Identical results were obtained in T. brucei-infected mice. Berenil treatment abolished the immune depression against sheep erythrocytes, but did not cure the animals, which relapsed with the development of a new state of immune depression. T. gambiense and T. brucei infections were always followed by a marked increase of serum IgM levels. Hypergammaglobulinemia was also induced in relapsing T. equiperdum-infected mice treated with Berenil. No immune depression against sheep erythrocytes could be detected. It appeared that immune depression was not the result of clonal exhaustion (measured by the serum IgM level) but seemed to be closely associated with the presence of living trypanosomes.

Hypertriglyceridemia associated with Trypanosoma brucei brucei infection in rabbits: role of defective triglyceride removal

Rabbits infected with Trypanosoma brucei brucei develop a hypertriglyceridemia characterized by an increase in very low density lipoprotein and, to a lesser extent, low density lipoprotein, with a decrease in high density lipoprotein. Triglyceride production studies showed that the triglyceride production rate was not significantly different in trypanosome-infected rabbits from controls. Studies of triglyceride degradation using very low density lipoprotein triglyceride endogenously labelled with [3H]palmitate demonstrated a marked slowing of triglyceride removal in the infected rabbits when compared to controls. Lipase activity in post-heparin plasma was found to be deficient in trypanosome-infected animals. Furthermore, the greater the decrease in lipolytic activity, the greater the increase in serum triglyceride level. We conclude that the hypertriglyceridemia associated with T. b. brucei infection in rabbits results predominantly from a defect in triglyceride degradation.

Variable severity of glomerulonephritis in inbred rats infected with Trypanosoma rhodesiense. Correlation with immunoglobulin class-specific antibody responses to trypanosomal antigens and total IgM levels

Five strains of inbred rats (ACI, BUF, F344, WF and WL) were infected with Trypanosoma rhodesiense and killed at 28 days for renal pathology and serological studies. The BUF strain demonstrated the most consistent and severe glomerulonephritis, accompanied by high titer IgM antibodies to trypanosomes and high total IgM levels. The WL strain demonstrated mild glomerulonephritis but prominent PAS (+) intracytoplasmic inclusions in proximal convoluted tubules, accompanied by low titer IgM antibodies and slightly elevated total IgM levels. All strains had low to medium titer IgG1 and IgGa antibodies to trypanosomes. Serial serologic studies in BUF rats showed peak titers of IgM, IgGa and IgG1 antibodies to trypanosomal antigens at 10 days. Immune complexes as measured by a C1q binding assay were elevated at 10 days, 3 days following the first detectable antibody responses, and remained so through the 30th day.

Immunologic reactions associated with anemia, thrombocytopenia, and coagulopathy in experimental African trypanosomiasis

Rats infected with Trypanosoma brucei rhodesiense developed anemia, thrombocytopenia, and hypocomplementemia. Anemia, thrombocytopenia, and sharp reductions in parasitemia were associated with elevated titers of cold-active hemagglutinin, antibody to fibrinogen/fibrin-related products, and immunoconglutinin. Depletion of lytic complement, prolonged partial thromboplastin times, and presence of fibrin monomers in the blood occurred at the time anemia and significant elevations in precipitable immune complexes were observed. Terminally, consumption of immunologic factors coincided with accelerated partial thromboplastin times. At death, convulsions and hemoptysis with labored breathing suggested that the animals died of respiratory failure and that disseminated intravascular coagulation may have occurred. It is suggested that microthrombiosis might have resulted from the immunologic interaction of complex-coated blood cells with immunoconglutinin and contributed to the terminal disease signs.

Meningoencephalitis in chronic Trypanosoma brucei rhodesiense infection of the white mouse

A more recently isolated strain of T.b. rhodesiense (eatro 1989) induced a chronic infection in most of 180 intraperitoneally infected NMRI-mice, surviving 6 to 9 weeks on an average. A meningoencephalitis beginning with a meningitis one week after infection and being fully developed after 4 weeks was demonstrable by investigating 22 animals killed at random between 7 and 42 days after infection. The inflammatory reactions observed correspond to those known from the late stage of human trypanosomiasis in their nature and way of spreading. Hence, this infection seems to offer a suitable model for studying a human like meningoencephalitis and for screening of compounds for activity during the late stage of human sleeping sickness.

[Trypanosomiasis presenting with trypanids and complicated by myopericarditis (author's transl)]

In a 26-year-old man who had spent time in a trypanosome endemic zone, lesions of erythema marginatum progressing by acute exacerbations for 2 years despite various forms of treatment led to the discovery of a multiple lymphadenopathy and a greatly accelerated sedimentation rate. These findings suggested a diagnosis which was confirmed by the discovery of Trypanosoma gambiense in the blood and lymph node aspirate. In addition, there was an albumino-lymphocytic reaction in the cerebrospinal fluid. Finally, an atrioventricular block was discovered. All these symptoms and signs responsed to treatment with melarsoprol but a pericardial reaction developed, possibly of immunoallergic origin.

Effect of chronic Trypanosoma brucei infection on the course of louping ill virus infection in mice

The course of louping-ill virus infection in mice chronically infected with Trypanosoma brucei was investigated. The mean survival time of mice infected with virus alone was 10.2 days, compared to 12.8 days in mice infected with T. brucei 14 days before virus challenge, and the cumulative mortality in the two groups was 62.5 and 90%, respectively. Virus was only inconsistently detected in the blood of mice given virus alone but was regularly present at high titers for up to 12 days in the blood of mice previously infected with T. brucei. Titers of virus in brains were also higher in dually infected mice, and encephalitis was of greater severity. These results indicate that the immunosuppressive effect of chronic trypanosomiasis may markedly increase susceptibility to acute virus infection. In addition, it is concluded that vector-vertebrate relationships of arthropod-transmitted viruses may be altered by concurrent trypanosome infection.

Proliferative glomerulonephritis, hypocomplementemia, and nucleic acid antibodies in rats infected with Trypanosoma rhodesiense

Host immunologic responses were studied in Sprague-Dawley rats infected with a human isolate of Trypanosoma rhodesiense. Retro-orbital sinus bleedings were obtained on days 0 and 14 and at 21 or 28 days. Infected and control rats were sacrificed on day 21 or 28 of the infection. Mild glomerulitis, as assessed by increased cellcularity and/or widening of the mesangial region, was apparent in 6 of 7 infected animals. Finely granular deposits of IgM and IgGl were found in most glomeruli with less prominent deposits of IgGa and IgA. Focal cortical mononuclear interstitial infiltrates were present in 2 of 7 rats. Subepithelial or mesangial electron dense deposits were present in the glomeruli of infected rats. Hypocomplementemia was present by day 21 and involved both the classical and alternative pathways of complement activation. Antibodies to native DNA and single-stranded RNA were present by day 21. These studies indicate the feasibility of studying trypanosomal glomerulonephritis in rats and will provide a convenient model for detailed immunologic and morphologic investigation of host immune responses in African trypanosomiasis.

Mechanisms of the anemia in trypanosomiasis: studies on the role of the hemolytic fatty acids derived from Trypanosoma congolense

Trypanosoma congolense releases a number of hemolytic free fatty acids on autolysis of which the most potent is linoleic acid. These fatty acids can lyse washed rat and bovine erythrocytes in vitro. Autolysed T. congoleuse will cause increased fragility of erythrocytes in whole rat blood but not in whole bovine blood. The lack of effect of these fatty acids on bovine erythrocytes tends to be confirmed by the failure of this material to influence the survival of these cells in vivo. Calculations based on the amount of free fatty acids required to cause hemolysis in vivo also confirm that this mechanism of erythrocyte destruction is probably unimportant in bovine trypanosomiasis.

Pancarditis with valvulitis in endomyocardial fibrosis (=emf) and in human African trypanosomiasis (= hat). A comparative histological study of four Ugandan cases

The study compares the histotopographical lesions of two cases of endomyocardial fibrosis with those of two hearts in sleeping sickness, all of them from Uganda. There was considerable overlapping of the fibrosed zones in endomyocardial fibrosis and the corresponding sites occupied by the chronic inflammatory process in trypanosomiasis. There was a tendency towards fibrosis in the hearts of trypanosomiasis while, in endomyocardial fibrosis, there were mild focal chronic cellular infiltrations. This overlapping and to some extent similarities would suggest that the two conditions may only differ in evolution in time and intensity and that they may be the result of the same inflammatory process. Stipulating a cardiac tropism for African trypanosomes, it is suggested that some African cases of endomyocardial fibrosis may be merely burnt-out lesions of trypanosomal pancarditis. Previous descriptions of carditis in human African and American trypanosomiasis are briefly reviewed, and the present findings are discussed in view of a possible trypanosomal aetiology in some African cardiomyopathies.

Pancarditis affecting the conducting system and all valves in human African trypanosomiasis

This paper describes the pathological features of 10 cases of human African trypanosomiasis occurring in Uganda over an 8-year period. Three cases were clinically proved, and in all 10 cases chronic meningoencephalitis and myocarditis were present. There was chronic pancarditis in 6 cases, and in 3 of these there was a generalized focal valvulitis and in 2 lesions of the conducting system. Previous descriptions of carditis in human African trypanosomiasis are briefly reviewed, and the present findings are compared with some cardiomyopathies as well as American human and experimental trypanosomiasis.

Coagulation studies in Gambian trypanosomiasis

Simple coagulation studies were carried out in 18 patients with advanced Trypanosoma gambiense infection. No evidence of disseminated intravascular coagulation was found. Many patients had a moderate degree of thrombocytopenia which may have been due to enhanced splenic trapping of platelets. Most patients had raised levels of fibrin degradation products in their cerebrospinal fluid, perhaps reflecting the presence of underlying cerebral and meningeal vascular damage. Addition of viable trypanosomes or of trypanosome extracts to human and rat blood did not produce significant thrombocytopenia in vitro.

Pathogenesis of the anemia in african trypanosomiasis: characterization and purification of a hemolytic factor

Acute anemia is a major feature of african trypanosomiasis. It has been shown to be of hemolytic nature. Hemolytic substances were found in serum from infected animals as well as in supernatant of trypanosome suspensions. A hemolytic pronase-sensitive factor of about 10000 M.W. has been purified from such supernatants.

Secondary lesions of the nervous system in some infectious and toxic--allergic conditions in Zambia

A number of toxic or toxic-allergic manifestations were discovered on careful examination of patients admitted in Chipata General Hospital with infective or febrile illnesses. A total of 111 patients were found to present with various forms of radiculities which resolved on treatment of the primary condition.

An evaluation of prednisolone as a routine adjunct to the treatment of T. rhodesiense

The purpose of this exercise was to evaluate the efficacy of a cortico-steroid in protecting the patient suffering from Rhodesian sleeping sickness from the complications of melarsoprol treatment. It is quite clearly shown that prednisolone was not effective in offering protection against the most serious treatment problem, encephalopathy. The apparent total success of the steroid in protecting the first group from the less severe treatment complications and in minimising early death need to be interpreted with some scepticism due to the smallness of the series. Nevertheless, it does help to substantiate the observations of others that in the case of the moribund patient, the immediate use of steroids might be life saving. On the basis of these findings the routine use of prednisolone as an adjunct to the treatment of T. rhodesiense was discontinued. The use of a cortico-steroid has been continued, however, as treatment for reactive encephalopathy, arsenical dermatitis and arsenical enteritis and with patients who are moribund on admission.

Thrombocytopenia in trypanosomiasis

In all of four patients with African trypanosomiasis, thrombocytopenia was present on admission to hospital or developed during the course of the illness. One patient with severe thrombocytopenia died following gastrointestinal haemorrhage shortly after admission to hospital. Kinetic studies in the other three patients showed marked pooling of platelets in the spleen in all, but severe shortening of platelet life-span in only one. Evidence of disseminated intravascular coagulation (DIC) was found in 3 patients, 2 of whom received heparin therapy. These findings provide evidence that thrombocytopenia is a feature of African trypanosomiasis and is due mainly to hypertrophy of the reticuloendothelial system which accompanies the infection. In some patients immune damage to platelets or platelet consumption as part of DIC may be an additional factor contributing to the thrombocytopenia.

Electrocardiographic changes in African trypanosomiasis caused by Trypanosoma brucei rhodesiense

The electrocardiographic findings in 40 patients with Trypanosoma brucei rhodesiense infection are reported. Using rigid diagnostic criteria 7 out of 18 patients (39%) had abnormal electrocardiograms before any form of therapy and 22 of the 40 patients (55%) had abnormal electrocardiograms at some stage of the disease or its treatment. The electrocardiographic abnormalities are described and discussed and the literature is reviewed.